Browsing by Subject "Bioeconomy"

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Biotechnological conversion of lignocellulose hydrolyzates : model microorganisms for a bio-based economy
(2020) Horlamus, Felix; Hausmann, Rudolf
Lignocellulose has substantial potential as a carbon source in a bio-based economy. It is the most abundant renewable raw material on earth and is available in large quantities as waste from the agriculture, food and wood industry. It is composed mainly of the polymers lignin, cellulose and hemicellulose. In contrast to glucose derived from cellulose, hemicellulose sugars often remain unused although 60 billion tons of hemicelluloses are produced annually. Hemicelluloses are a group of heterogeneous polysaccharides consisting of different monomers such as D xylose, D arabinose, D mannose and D galactose. Lignocellulose is mostly depolymerized in order to obtain fermentable sugars. During the depolymerization process, inhibitors such as organic acids or furan aldehydes can be formed or released, which could be problematical for biotechnological processes. The aim of this thesis was to develop and evaluate bacterial-based biotechnological processes capable of using hemicellulose sugars as a source of carbon. First, Pseudomonas putida KT2440 was chosen. Pseudomonades are claimed as a promising chassis in biotechnology due to their versatile and robust metabolism. Unlike other Pseudomonades, the strain KT2440 is classified as biosafety level 1 in the American Type Culture Collection (ATCC). However, these bacteria can metabolize glucose as the only lignocellulose monosaccharide. Cellvibrio japonicus was the second selected bacterium. This strain is not yet established as a microbial host in biotechnology, but can degrade a huge portfolio of plant cell wall polysaccharides and is also classified as biosafety level 1 in ATCC. The topic of the first publication was to engineer P. putida KT2440 strains for metabolizing the hemicellulose monosaccharides xylose and arabinose and characterize their growth behavior. Initially, an arabinose metabolizing strain with the araBAD operon and a xylose metabolizing strain with xylAB operon was constructed. Later on, these strains were cultivated in minimal salt medium with glucose, xylose and arabinose as carbon sources in Erlenmeyer flasks. The recombinant P. putida KT2440 strains metabolized xylose and arabinose with high growth rates comparable to glucose. It turned out that both engineered strains were able to grow on both pentoses as well as on mixtures of glucose xylose and arabinose. The intent of the second publication was to evaluate P. putida KT2440 as a platform model organism for bioconversion of lignocellulose hydrolyzates. Strains were cultivated in minimal salt medium with several hydrolyzates as carbon source in Erlenmeyer flask and bioreactor. In addition, the growth-inhibiting effect of major toxic substances contained in lignocellulose hydrolyzates on P. putida KT2440 was analyzed via cultivation experiments. Several suitable hydrolyzates were figured out for this strain. Formic acid and acetic acid proved to be relatively unproblematic under pH neutral conditions, whereas furfural and hydroxymethylfurfural (HMF) had a negative effect on the bacterial growth. A diauxic-like growth behavior was revealed via fed batch bioreactor cultivations, since pentoses were almost not consumed with sufficient glucose supply. Consequently, feed-medium was added step-by-step in the next experiment. The applied feed profile did lead to an almost complete metabolization of xylose. The purpose of the third publication was to evaluate C. japonicus as a potential host strain for the one‐step bioconversion of xylans into rhamnolipids. Cultivation experiments were performed in Erlenmeyer flasks filled with minimal salt medium and containing different carbon sources. Furthermore, the strain was transformed with the plasmid pSynPro8oT carrying rhlA (encodes acetyltransferase) and rhlB (encodes rhamnosyltransferase I) to complete the rhamnolipid metabolism. The strain grew on all main lignocellulose monosaccharides as well as, on different xylans. Mono rhamnolipids were produced with the engineered strain using xylans as carbon source. This is particularly interesting as most industrially relevant bacteria are not able to depolymerize wood polymers. As the product yields were quite low, there are still many challenges in order to achieve an economically efficient process. Nevertheless, to the best of our knowledge, it is the first published one step bioconversion of hemicellulose polymers into rhamnolipids. In total, P. putida KT2440 turned out as a flexible and powerful model organism and two xylose and arabinose metabolizing strains were constructed. Moreover, bioreactor cultivations with lignocellulose hydrolyzates were performed and a feeding strategy to overcome diauxic-like growth behavior was presented. A proof of concept for a one-step bioconversion of xylans into rhamnolipids with a recombinant C. japonicus strain was successfully demonstrated.
Climate‐based identification of suitable cropping areas for giant reed and reed canary grass on marginal land in Central and Southern Europe under climate change
(2023) Ferdini, Sofia; von Cossel, Moritz; Wulfmeyer, Volker; Warrach‐Sagi, Kirsten
Giant reed (GR) and reed canary grass (RCG) have emerged as promising perennial industrial crops for providing sustainable bioenergy from marginal land. However, there is great uncertainty among farmers and researchers about where these crops can be grown in the future due to climate change, which complicates a timely transition to a bioeconomy. Therefore, this study quantifies marginal land and suitable cropping areas for GR and RCG in Europe, as well as their overlap. To derive these areas, the present (1991–2020) and future (2071–2100, RCP8.5) growing degree days, growing season length, annual precipitation, and aridity index were analyzed using the E‐OBS observational dataset and EURO‐CORDEX regional climate simulations. The study concludes that while marginal land will decrease by ~18%, GR and RCG will profit from the changing European climate, increasing by ~24% and ~13%, respectively. Looking at regions of overlap between marginal land and the selected crops, a decrease of ~87% and an increase of ~462% is projected for RCG and GR, respectively. This is due to marginal land shifting southward, benefitting the warm‐season grass GR, while RCG prefers cooler climates.
Coupled biogas and fiber production from agricultural residues and energy crops with steam explosion treatment
(2023) Hülsemann, Benedikt; Baumgart, Marian; Lenz, Leonhard; Elviliana,; Föllmer, Marie; Sailer, Gregor; Dinkler, Konstantin; Oechsner, Hans
The global demand for packaging materials and energy is constantly increasing, requiring the exploration of new concepts. In this work, we presented a bioeconomic concept that uses steam explosion and phase separation to simultaneously generate fibers for the packaging industry and biogas substrate for the energy sector. The concept focused on fiber-rich residues and fiber-rich ecological energy crops from agriculture. Feasibility of the concept in the laboratory using feedstocks, including Sylvatic silphia silage, Nettle silage, Miscanthus, Apple pomace, Alfalfa stalks, and Flax shives was confirmed. Our results showed that we were able to separate up to 26.2% of the methane potential while always extracting a smaller percentage of up to 17.3% of organic dry matter (ODM). Specific methane yields of 297–486 LCH4 kgODM−1 in the liquid and 100–286 LCH4 kgODM−1 in the solid phase were obtained. The solid phases had high water absorption capacities of 216–504% due to the steam explosion, while the particle size was not significantly affected. The concept showed high potential, especially for undried feedstock.
Design and evaluation of a 3D‐printed, lab‐scale perfusion bioreactor for novel biotechnological applications
(2023) Merkel, Manuel; Noll, Philipp; Lilge, Lars; Hausmann, Rudolf; Henkel, Marius
3D‐printing increased in significance for biotechnological research as new applications like lab‐on‐a‐chip systems, cell culture devices or 3D‐printed foods were uncovered. Besides mammalian cell culture, only few of those applications focus on the cultivation of microorganisms and none of these make use of the advantages of perfusion systems. One example for applying 3D‐printing for bioreactor development is the microbial utilization of alternative substrates derived from lignocellulose, where dilute carbon concentrations and harmful substances present a major challenge. Furthermore, quickly manufactured and affordable 3D‐printed bioreactors can accelerate early development phases through parallelization. In this work, a novel perfusion bioreactor system consisting of parts manufactured by fused filament fabrication (FFF) is presented and evaluated. Hydrophilic membranes are used for cell retention to allow the application of dilute substrates. Oxygen supply is provided by membrane diffusion via hydrophobic polytetrafluoroethylene membranes. An exemplary cultivation of Corynebacterium glutamicum ATCC 13032 supports the theoretical design by achieving competitive biomass concentrations of 18.4 g L−1 after 52 h. As a proof‐of‐concept for cultivation of microorganisms in perfusion mode, the described bioreactor system has application potential for bioconversion of multi‐component substrate‐streams in a lignocellulose‐based bioeconomy, for in‐situ product removal or design considerations of future applications for tissue cultures. Furthermore, this work provides a template‐based toolbox with instructions for creating reference systems in different application scenarios or tailor‐made bioreactor systems.
Evaluation of bio-oil produced from fast pyrolysis of lignocellulosic biomass as carbon source for bacterial bioconversion
(2020) Arnold, Stefanie; Hausmann, Rudolf
Scarcity of fossil resources, climate change and growing world population demand the transition from a fossil-based economy towards a bioeconomy – a knowledge-based strategy which relies on the efficient and sustainable integration of bio-based resources into value-added process chains. As lignocellulosic biomass is an abundant renewable resource which does not directly compete with food and feed, its deployment in biorefineries is of special interest for a sustainable bioeconomy. Owing to its compact and complex structure, suitable conversion techniques need to be selected. Combinations of thermochemical and biochemical conversion technologies are considered to be a promising approach regarding a fast and efficient conversion of lignocellulosic biomass into value-added products. Bio-oil derived from fast pyrolysis of lignocellulosic biomass is a complex mixture and composed of water and a wide variety of organic components. Among these components pyrolytic sugars and small organic acids are particularly interesting as potential carbon sources for microbial processes. However, bio-oil also comprises many unidentified substances, as well as components which are known to display adverse effects on microbial growth. To evaluate the potential and challenges of bio-oil as an alternative and sustainable carbon source for bacterial bioconversion this thesis was divided into three parts (Figure 1). In Part I different pretreatment strategies were applied and evaluated regarding their effect on stability and detoxification of bio-oil fractions. For this purpose, the organic solvent tolerant bacterial strain Pseudomonas putida KT2440 was applied as a reference system and cultivated on different pretreated bio-oil fractions. It was shown that solid phase extraction is a suitable tool to obtain bio-oil fractions with significantly increased stability along with less inhibitory substances. Part II is focused on the evaluation of small organic acids mainly present in bio-oil with respect to their suitability as feedstock for bacterial growth. Four biotechnological production hosts Escherchia coli, Pseudomonas putida, Bacillus subtilis and Corynebacterium glutamicum were cultivated on different concentrations of acetate, mixtures of small organic acids, as well as pretreated bio-oil fractions as carbon source for their growth. Results reveal that P. putida, as well as C. glutamicum metabolizes acetate – the major small organic acid generated during fast pyrolysis of lignocellulosic biomass – as sole carbon source over a wide concentration range and grow on mixtures of small organic acids present in bio-oil. Moreover, both strains show a distinct potential to tolerate inhibitory substances within bio-oil. Part III describes the growth behavior of a genetically engineered, nonpathogenic bacterium Pseudomonas putida KT2440 and its simultaneous heterologous production of rhamnolipid biosurfactants on bio-oil derived small organic acids and pretreated fractions. Results suggest that both maximum achievable productivities and substrate-to-biomass yields are in a comparable range for glucose, acetate, as well as the mixture of acetate, formate and propionate. Similar yields were obtained for a pretreated bio-oil fraction, although with significantly lower titers. In conclusion, this thesis shows that microbial valorization of bio-oil is a challenging task due to its highly complex and variable composition, as well as its adverse effects on microbial growth and issues with analytical procedures. This work depicts a proof of concept by outlining a potential biorefinery route for microbial valorization of pretreated bio-oil and its unexploited side streams. It provides a step in search of suitable bacterial strains for bioconversion of lignocellulosicbased feedstocks into value-added products and thus contributes to establishing bioprocesses within a future bioeconomy.
Governance challenges of developing biomass-based value webs : the case of maize in Ethiopia
(2018) Mengistu, Tilahun Woldie; Birner, Regina
In recent years, the need to move from an economy based on fossil resources to an economy based on biological resources has gained increasing attention. The bioeconomy has the potential to ensure sustainable growth by enhancing the usage of untapped biomass resources. This potential is particularly pronounced in sub-Saharan Africa and has attracted the attention of both governments and the international donor community. To use the potential of the bioeconomy in a sustainable way without jeopardizing food security, it is essential to increase the productivity and the efficiency of the production and utilization of biomass. Using the maize production in Ethiopia as a case study, this thesis aims to identify strategies that will contribute to a higher productivity and better utilization of biomass in the emerging bioeconomy. Maize has been selected for this case study because it is on one the one hand a major food crop in Africa while it has, on the other hand, the potential to provide biomass for multiple uses in the bioeconomy. Ethiopia is well suited for the case study because it is confronted with major challenges of food security, while it has at the same time a large underutilized potential to increase the production of biomass for the bioeconomy. The thesis focuses on two themes: One is an analysis of the seed system, because maize seed supply has been identified as a major bottleneck to increasing productivity in the production of biomass. Ethiopias seed sector has been plagued with problems of seed quality regulation, certification, dominance of informal seed sourcing, and inefficient distribution system, among other governance challenges. There have been major reform efforts in recent years, but there is not sufficient empirical evidence on how these reforms have fared. The second theme to the thesis is the utilization of the biomass from maize. This topic has been selected because there is a dearth of empirical evidence on the usage of the different components of maize (e.g. cob, stalk, leaves etc.) for several purposes, and its implications for household food security. Against this background, the broad objective of this thesis is threefold: (1) to analyze the institutional arrangements for maize seed quality regulation, and uncover the governance challenges therein; (2) to identify the governance challenges in the hybrid maize seed distribution system and analyze farmers’ preferences of the select attributes for hybrid seed distribution; and (3) to assess usages of the different components of maize biomass, and examine its implications for food security. The thesis is based on a mixed methods approach. Data were collected using both qualitative and quantitative techniques. The study of seed quality regulation relies primarily on qualitative data collected through Process Net-Maps, focus group discussions, key informant interviews and direct observation in three maize growing districts. For the second and third objectives, data were collected using household survey and a choice experiment covering 325 farmers, Process Net-Maps, focus group discussions and key informant interviews. We employ the latent class and endogenous switching regression models to analyze the choice experiment data on farmers’ preference for the distribution attributes and effect of farmers’ diverse biomass use decision on food security, respectively. The findings of the thesis contribute to the wider debates on governance and institutional challenges of ensuring food security through development of the bioeconomy, taking maize as an important bioeconomy crop. By investigating the roles of different stakeholders in the seed system, the study finds that the systems suffer from a number of governance and institutional challenges such as corruption, implementation gaps that arise due to capacity limitation and lack of political will to support private sector participation. The study suggests ways to overcome the governance challenges, which include enhancing internal as well as external quality control mechanisms, redefining certification standards, making certification services transparent, participatory and cost-effective, and a strong political will to fully implement reforms by promoting private sector participation. Additionally, the positive and homogeneous preferences for attributes like seed quality, types of sales outlets and access to credit that are shared by the majority of the surveyed farmers’ show the extent to which reform outcomes deviated from the needs of farmers. The study identified farmers’ preferences regarding the question of how they would like to access hybrid seeds and recommends ways to overcome the governance challenges in seed distribution in Ethiopia. In addition to examining problems regarding production, the study confirmed that maize biomass utilization is crucial for food security and development of bioeconomy. The findings show that maize biomass is underutilized in the country because of lack of enabling conditions such as access to extension and information, marketing channels, availability of multi-purposes maize varieties and value-adding technologies. The findings led to the recommendation that policy innovation to provide better access to these conditions is essential to achieve growth in the maize sector and food security.
Governance of emerging biomass-based value webs in Africa : case studies from Ghana
(2018) Poku, Adu-Gyamfi; Birner, Regina
Rising global demand for food as well as for feed and biomass-based raw materials such as fuel and fibre crops has increased pressure on the agricultural sector, especially in Sub-Saharan Africa. The expected trend of increased demand for more diverse biomass-based produce from agricultural land effectively transforms the agriculture sector from just a food-supplying to a biomass-supplying sector in the growing international bioeconomy. This transition is leading to the development of biomass-based value webs whereby there are complex systems of interlinked value chains in which food, fodder, fuels, and other raw materials are produced, processed, traded and consumed. Against this background, this thesis aims to evaluate the appropriate roles of the public, private and third (civil society) sectors in facilitating the transformation of the agricultural sector in the developing bioeconomy in Ghana. The study focuses on the emerging value webs of cassava (Manihot esculenta) and maize (Zea mays), which are the two most important staple crops in Ghana.
Integrated rural and urban agricultural systems for the sustainability transition towards the bioeconomy
(2021) Winkler, Bastian; Lewandowski, Iris
The goal of the bioeconomy is a fundamental transition of both the economy and society towards sustainability. Replacing fossil resources by biomass for the provision of food, feed, fibre and fuel/energy (the 4F’s) will result in a substantial increase in demand for agricultural products. The consequent intensification of agricultural production, however, needs to be achieved while alleviating the societal challenges of the 21st century. The bioeconomy provides a knowledge-based, cross-sectoral and systemic pathway to increase agricultural production that involves all relevant stakeholders in the sustainability transition. This interdisciplinary thesis investigated the contribution that three selected bioeconomic approaches can make to the sustainable intensification of agricultural production, encompassing the growing urban population on the demand side and the numerous smallholder family farmers in countries of the global South on the supply side. The first study develops the ‘Integrated Renewable Energy Potential Assessment’ (IREPA) approach that involves smallholder farmers in planning and selection of renewable energy (RE) technologies for implementation into their agricultural systems. The bottom-up potential assessment, participatory learning and action research and multi-criteria decision analysis supported the smallholders in two case studies in rural South Africa and India in the identification of locally appropriate RE technologies. The second study uses IREPA to explore smallholders’ perception of agricultural RE production. Social, environmental, technical, institutional and economic factors are analysed to identify drivers of and barriers to RE implementation into smallholder agricultural systems. Mainly environmental factors, in particular climate change impacts, motivate smallholders to produce RE, while social factors (social cohesion, gender aspects, well-being, food and water security) determine the actual change. The barrier of high upfront investment costs can be eliminated by falling RET prices, the development of novel rural RE business models and institutional support. In addition, growing smartphone penetration rates in rural areas and open-access online information enables do-it-yourself RET operation and maintenance. Integrated approaches and such insights are crucial for the targeted formulation of agricultural development policies and stakeholder involvement in the sustainability transition towards a bioeconomy. The third study investigates the characteristics of urban gardening in Germany and its potential to encourage sustainable consumer behaviour, based on a review of 657 urban gardening project websites and an online survey involving 380 project participants. The results reveal multiple social, environmental and economic benefits of urban gardens for sustainable city development. The diverse gardener communities actively promote sustainable consumer behaviour by (unintentionally) applying several methods known to encourage pro-environmental behaviour. Hence, urban gardens are transformative spaces that involve the growing urban population in the societal transition towards a bioeconomy. In the context of sustainable intensification of biomass production in rural areas, the fourth study investigates the contribution of environmental service assessment and monetization in agricultural systems, using the example of the perennial biomass crop miscanthus for biofuel production. The valorisation makes environmental services - such as soil fertility improvement, carbon sequestration, water and air purification – tangible. This can incentivise payments to farmers for the provision of these public goods. Enhancing and utilising environmental services through nature-based solutions is a promising pathway to sustainable intensification, providing a shift from input-based towards process-based agricultural production. Finally, it can be concluded that integrated approaches which connect different production systems, disciplines and stakeholders are central for the development of the bioeconomy: - The integration of sustainable technologies, such as RE, into agricultural systems requires case-based research and participation of local stakeholders in project planning, decision making and targeted policy formulation. - The integration of the growing urban population in the sustainability transition can be supported by urban gardening because it promotes sustainable consumer behaviour. - The integration of nature-based solutions into agricultural systems enhances environmental service provision and supports the shift from input-based towards process-based agricultural systems. The approaches discussed in this thesis can support the sustainable intensification of agriculture, serve to re-connect the perspectives of rural producers and urban consumers, and enable the involvement of large portions of society in the sustainability transition towards the bioeconomy.
Methodological approaches for assessing the environmental performance of perennial crop-based value chains
(2017) Wagner, Moritz; Lewandowski, Iris
In a developing bioeconomy, the demand for biomass for industrial purposes is expected to increase significantly. This demand needs to be met in a sustainable way and without compromising food security. With this goal in mind, resource-efficient lignocellulosic crops, such as perennial energy grasses, are often cited as a biomass source with low negative impacts on the environment. Under European conditions, miscanthus is the leading perennial energy grass because of its high biomass and energy yield potential. It is a C4 plant, which achieves dry matter biomass yields of up to 20 Mg ha−1 yr−1 when harvested in later winter, and up to 30 Mg ha−1 yr−1 when harvested green in October. Currently the main utilization route of miscanthus is direct combustion for heat generation, but the biomass can also be used for various other applications, such as biofuels and insulation material. Several studies have analysed the environmental performance of perennial crop-based value chains, but most of these only assessed the Global Warming Potential (GWP). However, the GWP alone is not an adequate indicator for the holistic assessment of the environmental performance of such value chains. In addition, these studies often used generic data and applied varying assumptions, which makes a comparison of different value chains difficult. The main goal of this thesis is to draw up recommendations for future assessments of the environmental performance of perennial crop-based value chains. For this purpose, five research objectives were formulated: 1) to identify the key parameters influencing the environmental performance of perennial crop-based value chains; 2) to analyse which impact categories are most relevant when assessing the environmental performance; 3) to assess the differences between various perennial-crop based value chains; 4) to assess the environmental performance of the utilization of marginal land to grow perennial crops for industrial purposes; and 5) to analyse and compare the environmental performance of annual and perennial crops in the example value chain ‘biogas production’. To achieve these research objectives, the environmental performance of several perennial crop-based value chains was analysed in various impact categories applying the same underlying assumptions and using field data obtained under ceteris paribus conditions. The analysis was carried out using the globally recognised Life Cycle Assessment (LCA) methodology, which is standardized by two ISO norms (14040/44). The results revealed that biomass yield is one of the most important parameters influencing the environmental performance of perennial crop-based value chains. An increase in yield of 50%, for instance, leads to an increase in carbon mitigation potential in a comparable range (46%). Furthermore, the marked influence on the environmental impact mitigation potential of both fertilizer-induced emissions and selection of the reference system was demonstrated. For example, if the reference system is changed from light fuel oil to natural gas, the substituting by heat generated from the combustion of miscanthus biomass increases the net impact in the category ‘particulate matter formation’ by 220%. The relevance of different impact categories was analysed for various perennial crop-based value chains using a normalisation approach. The results clearly indicated that a holistic assessment of the environmental performance of perennial crop-based value chains should at least include the impact categories ‘marine ecotoxicity’, ‘human toxicity’, ‘agricultural land occupation’, ‘freshwater eutrophication’ and ‘freshwater ecotoxicity’. In future assessments, it is recommended to include the impacts of land-use on both biodiversity (using species richness as an indicator) and soil quality (using SOM as an indicator). The comparison of the environmental performance of different perennial crop-based value chains revealed clear environmental advantages of the cascade use of biomass. An example is the production of miscanthus-based insulation material, which is first used as a building material and then incinerated to generate heat and electricity. The results also demonstrate that, despite low biomass yield on marginal land, miscanthus-based value chains have a substantial environmental impact mitigation potential when substituting a fossil-based reference system. Furthermore, the comparison of annual and perennials crops as biogas substrates showed that perennial crops, and in particular miscanthus, have a considerably better environmental performance in the impact categories ‘climate change’ (up to -73%), ‘fossil fuel depletion’ (up to -79%), ‘freshwater eutrophication’ (up to -69%), ‘marine eutrophication’ (up to -67%), and ‘terrestrial acidification’ (up to -26%). In all four studies included in this thesis, it was observed that the data used for the biomass cultivation in particular, such as yield and fertilizer-induced emissions, have a considerable influence on the environmental performance. This data is highly site- and crop-specific and is strongly dependent on the agricultural management system applied. Based on the results of this thesis, the common practice of using generic data in assessments of the environmental performance of perennial crop-based value chains should be rejected. In order to obtain realistic results, the use of site- and crop-specific data is highly recommended.
Modelle und Lösungsverfahren zur langfristigen Planung der Stromproduktion einer flexiblen Biogasanlage unter Berücksichtigung von Verschleiß
(2021) Butemann, Hendrik; Schimmelpfeng, Katja
One of the most important measures against climate change is the shift from fossil to renewable energies. Many countries have therefore made it their goal to increase the share of renewable energies for electricity generation. In Germany, the share in 2019 was 40.2%, of which biomass accounted for 20.6%. This category includes biogas plants, which, unlike other sources of renewable energy, have the advantage of not being dependent on certain weather conditions. They are considered a flexible option for electricity generation because they can produce electricity when neither the sun is shining nor the wind is blowing. When the first biogas plants were put into operation, revenues from electricity production could be maximized by having the combined heat and power unit (CHP) associated with the biogas plant generate electricity continuously. To take advantage of the flexibility of biogas plants, German legislators introduced premiums that contained incentives to produce electricity during periods of low supply from other renewable energy sources. Since then, biogas plant operators have been able to maximize their revenues when the CHP produces electricity on demand, i.e., in start-stop mode. However, a large number of starts and stops of the CHP causes altered wear and tear and must be taken into account in the long-term planning of the electricity production of a biogas plant. The aim of this dissertation is therefore to use operations research methods to develop cyclical electricity production plans for biogas plants that take into account the wear and tear of the CHP and the timing and costs of maintenance activities in order to support biogas plant operators in maximizing their revenues. For this purpose, first a classification of electricity production planning of biogas plants into the planning tasks along the biomass-based supply chain is given. Subsequently, the basics of biogas plants are explained, which include their relevance in Germany, their way of operation, service and maintenance as well as the legal framework for their operation. The research gap, which is filled by this dissertation, results from the literature review on quantitative approaches for the operation of biogas plants. It shows that there is still no research work that sufficiently addresses the wear and tear of CHP in flexible operation and the planning of maintenance activities in connection with electricity production. Therefore, a conceptual optimization model is developed that accurately replicates the non-linear wear that occurs in reality and thus enables simultaneous planning of electricity production and maintenance activities. For better applicability with standard solvers, the model is additionally linearized. A case study based on real-world data reveals that a flexible biogas plant achieves higher total revenues than a continuously operated biogas plant under the conditions prevailing in Germany, even when maintenance costs are taken into account. The conceptual optimization model is then extended to produce a cyclical plan that biogas plant operators can apply on a weekly basis. In the following chapter, a greedy heuristic for generating a starting solution as well as a genetic algorithm and a tabu search are developed with the goal of reducing the computation time when solving the extended model. For this purpose, the basics of the individual solution methods are first explained and the input data are adapted to the problem with the help of parameter tuning. An extensive numerical study, in which the input parameters electricity prices, costs for maintenance activities, wear and tear of the CHP and biogas storage capacity are varied, compares the performance of the methods with that of the extended optimization model. In all scenarios, the tabu search determines the best result in low runtime. A summary and an outlook on further research opportunities conclude the dissertation.
Navigating the biocosmos: Cornerstones of a bioeconomic utopia
(2023) Onyeali, Wolfgang; Schlaile, Michael P.; Winkler, Bastian
One important insight from complexity science is that the future is open, and that this openness is an opportunity for us to participate in its shaping. The bioeconomy has been part of this process of “future-making”. But instead of a fertile ecosystem of imagined futures, a dry monoculture of ideas seems to dominate the landscape, promising salvation through technology. With this article, weintend to contribute to regenerating the ecological foundations of the bioeconomy. What would it entail if we were to merge with the biosphere instead of machines? To lay the cornerstones of a bioeconomic utopia, we explore the basic principles of self-organization that underlie biological, ecological, social, and psychological processes alike. All these are self-assembling and self-regulating elastic structures that exist at the edge of chaos and order. We then revisit the Promethean problem that lies at the foundation of bioeconomic thought and discuss how, during industrialization, the principles of spontaneous self-organization were replaced by the linear processes of the assembly line. We ultimately propose a bioeconomy based on human needs with the household as the basic unit: the biocosmos. The biocosmos is an agroecological habitat system of irreducible complexity, a newhumanniche embedded into the local ecosystem.
Ökonomische Bewertung regionaler Wettbewerbspotentiale verschiedener landwirtschaftlicher Biomassen im Rahmen der Bioökonomie unter besonderer Berücksichtigung Baden-Württembergs
(2020) Petig, Eckart; Bahrs, Enno
The finite nature of fossil resources and climate change pose major challenges to the global society and require a comprehensive transformation of the current economic system. One important aspect of this transformation, also known as bioeconomy, is the transition from a fossil-based to a bio-based supply of raw materials. In this context, agricultural production represents an important supplier of raw materials, which in Germany is already characterized by a strong competition for the scarce land. The scarce land is a major challenge of the expansion of the use of agricultural biomass for the bioeconomy. Accordingly, the derivation of the potential of agricultural biomass for bioeconomy requires consideration of the tradeoffs between various utilization paths. In this context, economic models can be valuable methods, which on one hand are able to depict the trade-offs of different value chains and can, on the other hand, incorporate the uncertainty by developing suitable scenarios. The aim of this thesis is the evaluation of the potential of different agricultural biomasses for the bioeconomy and to analyze the associated effects on agricultural production structures in Baden-Wuerttemberg. In chapter 2 the potential of grassland as a biogas substrate is evaluated, which might be important for the bioeconomy in the future. Due to the more complex harvesting process and partly unfavorable production conditions, grassland has higher production costs compared to arable biogas substrates. The consideration of iLUC Factors with high prices for GHG emissions could improve the competitiveness of grassland to such an extent that it is competitive with the production of biogas substrates on arable land. However, silage maize is often the more favorable biogas substrate in many respects, as chapter 3 shows by means of a site modeling for biogas plants in Baden-Wuerttemberg. In chapter 4 and 5 the potential of straw for energetic and material use is analyzed. These investigations are based on the combination of EFEM with the techno-economic location optimization model BIOLOCATE. The results clearly show the interaction between the economies of scale and the rising raw material supply costs. On the one hand, the average investment costs decrease with increasing plant size, but on the other hand the raw material costs increase, because the transport distances increase and an increasing demand for biomass results also in higher market prices. Additionally, the results show that straw can make a fundamental contribution to the bioeconomy by providing regional bioenergy and as feedstock for material value chains. However, even the use of by-products can have effects on cultivation structures and thus, reduce the production of agricultural biogas substrates, among other things. In Chapter 6 the effects of macroeconomic expansion paths of the bioeconomy on agricultural production structures in Baden-Wuerttemberg are investigated. For this purpose, the results of an iterative model coupling between the agricultural sector model ESIM and the energy sector model TIMES-PanEU of four bioeconomic scenarios are scaled down from national level to regional and farm level using EFEM. The results show different impacts on farm types and thus illustrate the advantages of a differentiated analysis of the expansion of the bioeconomy. Therefore, farms with mainly extensive production methods such as suckler cow husbandry do not profit from the expansion of the bioeconomy due to unfavorable production conditions, while especially large arable farms in fertile regions would benefit disproportional more than the average. Basically, the results reveal limits to the mobilization of additional biomass potential. The reason for this is the already high cultivation intensity of agricultural production in Germany, in which the expansion of one production restricts production of another due to competition for the limited agricultural land. For grassland, the results show that the decline in grassland-based cattle farming and unfavorable economic conditions can lead to a significant increase of unused grassland. Grassland thus presents itself as a promising resource for biomass production for the bioeconomy, as it can provide important ecosystem services (e.g. biodiversity) in addition to the provision of raw materials. However, a political framework has to be established that promotes ecological services accordingly. Finally, in chapter 7 additional research needs are identified, which include further development of the methodological approach. These comprise an extension of the analysis by macroeconomic models to integrate interactions with the material use in a more detailed way. Furthermore, an integration of ecological parameters is necessary for a holistic analysis in the context of bioeconomy.
Process water recirculation during hydrothermal carbonization as a promising process step towards the production of nitrogen-doped carbonaceous materials
(2021) Dominik, Wüst; Pablo, Arauzo; Sonja, Habicht; Fernando, Cazaña; Luca, Fiori; Andrea, Kruse
Hydrothermal Carbonization (HTC) refers to the conversion of biogenic wastes into char-like solids with promising perspectives for application, but a process water (PW) results which is difficult to dispose untreated. Thus, a biorefinery approach including one or two recirculation steps with the additional objective of improving the physico-chemical characteristics of the solid was performed in this study. During HTC, constitutive molecules such as saccharides, proteins and lignin of Brewer’s Spent Grains decompose into hundreds of organic compounds, following complex reactions. To get deeper insights a combination of proximate, ultimate and structural analysis for solid products as well as liquid chromatography for liquid products were the choice. The main reactions could be identified by key compounds of low and high molecular weight resulting from hydrolysis, dehydration, decarboxylation, deamination as well as amide formation and condensation reactions. Their intensity was influenced by the feedwater pH and reaction temperature. Via reactions of Maillard character up to around 90% of the dissolved nitrogen of the recirculated process water at 200, 220 and 240 °C result in the formation of nitrogen containing heterocycles or rather Quartnernary nitrogen incorporated into the hydrochar (HC). Thus, already one recirculation step during HTC at 240 °C promises the fabrication of high added-value materials, i.e. nitrogen doped carbonaceous materials.
A proposal for evaluating the economic viability of biorefineries against petrochemical benchmarks
(2024) Götz, Markus; Kruse, Andrea
Usually costs of bio‐based products are compared to those of their fossil counterparts, most often made from crude oil. This paper adds new insights into this kind of comparison and provides approaches as to how future innovations in biorefineries and bio‐based chemicals can be compared to commercial fossil alternatives. The shift to alternative carbon sources will lead to higher costs in the short term. However, expected changes in the crude oil market and regulatory effects will cause rising costs of fossil chemicals in the near future. This work also provides strategies for implementing increased prices.
The role of consumers in business model innovations for a sustainable circular bioeconomy
(2023) Lang, Stephanie; Minnucci, Giulia; Mueller, Matthias; Schlaile, Michael P.
Over the last decade, various governments and supranational bodies have promoted the development of a circular bioeconomy (CBE) as a response to sustainability challenges. The transition towards a CBE requires the collaboration of different actors in the innovation (eco)system. With this conceptual paper, we apply a circular business model lens to address the research question: “What are the archetypical roles of consumers in business model innovations for a sustainable CBE?” We use a combination of complementary theories from the circular economy and bioeconomy literature, evolutionary innovation economics, sustainability transitions research, the business model literature, and the work on active consumers. Considering consumers’ agency as a continuum between the manufacturer-active paradigm and the consumer-active paradigm, we propose: (i) consumers in the manufacturer-active paradigm can actively influence circular business models with their purchase decision; (ii) consumers can act as lobbyists and influencers for circular business model innovation; (iii) in their different roles as customer, user, repairer, and reseller, consumers can incentivize organizations to adapt their business models to their needs; (iv) consumers can become key partners in the process of defining the normative orientation of the innovation paradigm for a CBE; (v) consumers can actively co-create value by means of co-ownership (e.g., through platform cooperatives).
Strategic network planning in biomass-based supply chains
(2021) Fichtner, Stephan; Meyr, Herbert
Fossil resources are limited and will run short. Moreover, the extensive usage of fossil resources is discussed as a key driver for climate change which means that a changeover in basic economic and ecological thinking is necessary. Especially for energy production, there has to be a movement away from the usage of fossil resources and towards renewable resources like wind, water, sun, or biomass. Within the first part of this work a structured review of recent literature on the long-term, strategic planning of biomass-based supply chains is provided. Therefore, in the first step, the overall research field “bioeconomy” by means of the various utilization pathways of biomass is structured and the demand-oriented view of supply chain management models and the supply-oriented view of bioeconomy are combined. In the second step, a literature review of operations research models and methods for strategic supply chain planning in biomass-based industries are provided. Thirdly, trends are identified and conclusions about research gaps are drawn. One of the identified research gaps is to make biomass-based supply chains profitable on their own, i.e., without governmental subsidies. Therefore, new optimization models are necessary, which should be as close to reality as possible, by for example considering risks and actual surrounding constraints concerning the legal framework. Within the second part of this work, an approach for strategic optimization of biogas plants considering increased flexibility is developed. Biogas plants can produce their energy flexibly and on-demand if their design is adjusted adequately. In order to achieve a flexibly schedulable biogas plant, the design of this plant has to be adapted to decouple the biogas and electricity production. Therefore, biogas storage possibilities and additional electrical capacity are necessary. The investment decision about the size of the biogas storage and the additional electrical capacity depends on the fluctuation of energy market prices and the availability of governmental subsidies. This work presents an approach supporting investment decisions to increase the flexibility of a biogas plant by installing gas storages and additional electrical capacities under consideration of revenues out of direct marketing at the day-ahead market. In order to support the strategic, long-term investment decisions, an operative plant schedule for the future, considering different plant designs given as investment strategies, using a mixed-integer linear programming (MILP) model in an uncertain environment is optimized. The different designs can be evaluated by calculating the net present value (NPV). Moreover, an analysis concerning current dynamics and uncertainties within spot market prices is executed. Furthermore, the influences concerning the variation of spot market prices compared to the influence of governmental subsidies, in particular, the flexibility premium, are revealed by computational results. Besides, the robustness of the determined solution is analyzed concerning uncertainties. The focus of the third part of the work is to consider variable substrate feeding in the mentioned optimization approach because it is expected that variable substrate feeding and thus a demand-oriented biogas production can influence the optimized plant design. In order to support this extension, an operative plant schedule for the future, considering (non-) linear technical characteristics of the biogas plant and the legal framework is optimized. Therefore, mixed-integer linear programming models with integrated approximation approaches of non-linear parts, representing the biogas production rates, are constructed. Furthermore, the influences of fluctuating spot market prices, governmental subsidies, and biomass feedstock prices on the decisions are analyzed for a fictional case example, which is based on a biogas plant in southern Germany. These numerical experiments show that variable substrate feeding can play a decisive role during the optimization of a biogas plant schedule as part of a long-term design optimization. However, the size of the strategic optimization problem makes the use of a heuristic solution algorithm necessary.
Sustainable entrepreneurship and the bioeconomy transition
(2023) Hinderer, Sebastian; Kuckertz, Andreas
Transgressing planetary boundaries endangers the safe operating space for humanity. Thus, a transition of socioeconomic systems toward sustainable development is needed. Prior research elevated the role of sustainable entrepreneurship (SE) in the transition process toward sustainable development in general and the bioeconomy in specific. Bioeconomy strategies worldwide acknowledge the importance of entrepreneurship for the transition process. There is consensus in research that entrepreneurs are needed to implement the vision of a bioeconomy as defined in these strategies. However, it remains unclear how opportunities for entrepreneurial activity in the bioeconomy come into existence and how entrepreneurs contribute to the bioeconomy transition by acting on the provided opportunities. Thus, this dissertation aims to shed light on the interface of SE and the bioeconomy, specifically by investigating the interplay between SE and the bioeconomy transition in light of planetary boundaries and the role of entrepreneurs within the transition. The four empirical studies included in this dissertation take different perspectives on the interface of SE and the bioeconomy and thus contribute different insights to the overall picture drawn in this dissertation. For instance, Study 1 examines a transition pathway to a sustainable bioeconomy by involving an international expert sample in a Delphi survey and subsequent cross-impact analysis. Study 1 presents a list of events necessary to achieve the transition ranked by the experts to reflect their urgency. The cross-impact analysis facilitates combining the most urgent events to create an integrated model of the transition to a sustainable bioeconomy. The findings suggest that rather than bioeconomy strategies, technological progress leveraged by innovative bioeconomy startups and investments currently constitute the main bottleneck hindering a transition to a bioeconomy. Study 2 zooms into the level of new bioeconomy ventures. Based on interviews with ten bioeconomy entrepreneurs from six European countries, it investigates how entrepreneurial opportunities emerge in the bioeconomy context and what competencies entrepreneurs need to act on them. Conceptualizing the bioeconomy transition as an external enabler for SE, Study 2 opens new avenues for research on sustainable development and innovation policy. Furthermore, Study 2 shows that new venture creation in the bioeconomy requires unique knowledge and specific competencies. Study 3 asks how to scale sustainable new ventures and puts it in the context of the ongoing de-growth debate. In recent years the de-growth paradigm has gained popularity in the sustainability discourse. Questioning the absolute decoupling of economic growth from environmental degradation, de-growth proponents suggest downscaling production and consumption to reduce resource extraction and energy consumption. Applying latent class analysis to reveal de-growth attitudes among 393 surveyed entrepreneurs and subsequent regression analysis, Study 3 answers how de-growth attitudes among (sustainable) entrepreneurs are associated with their decision-making on scaling strategies for their ventures. Furthermore, it shows that the development level of the economy an entrepreneur is active in is an essential factor in the decision-making on scaling strategies. Study 4 investigates how sustainable new ventures gain legitimacy to acquire the necessary resources to grow. Previous research suggested being distinctive yet understandable as key to legitimacy for new ventures. However, Study 4 describes complex entrepreneurial identities, i.e., unconventional combinations of entrepreneurial identity claims from the founder and venture levels, as an additional source of legitimacy that benefits only sustainable new ventures but not conventional ones. Since sustainable startups aim to tackle complex problems, external audiences expect them to be different from established conventions of the status quo. An analysis of 15,116 crowdfunding campaigns and their creators’ user profiles via topic modeling and subsequent regression analysis supports this argumentation. The findings show that sustainable ventures with complex – or even odd – entrepreneurial identities receive more support from crowdfunders, while conventional ventures do not. Overall, this dissertation conceptualizes a bi-directional and potentially reinforcing relationship between SE and the bioeconomy transition by building on extant literature and collecting and analyzing new data in four empirical studies. Moreover, it highlights the role of entrepreneurs who need unique knowledge and specific competencies and differ significantly from conventional entrepreneurs in their behavior and entrepreneurial identity. Finally, this dissertation discusses how policy and societal norms can foster productive entrepreneurship that is innovative and sustainable within planetary boundaries.
The bioeconomy : a knowledge-based innovation paradigm to foster sustainability transformations
(2020) Urmetzer, Sophie; Pyka, Andreas
Notwithstanding 40 years of global climate policies, carbon dioxide emissions are still increasing and global surface temperature is still rising until today – with all its consequences to ecosystems and the fate of humanity on Earth. Current attempts to stop and reverse unsustainable developments that lead to the climate crisis and to other ecological and social disasters have proven rather ineffective. While there certainly are many reasons for this on the operative level, the dissertation is motivated by the assumption that countermeasures generally suffer from a lack of systemic framing of the wicked sustainability issues. What if solution approaches – despite being brought forward to the best of decision makers’ knowledge and belief – (only) are subject to a perceptual mistake in the way sustainable solutions are currently framed? I propose a change in perspective as decision making basis for improved sustainability governance. It is a call for getting to the systemic root causes of sustainability problems. To achieve a change in (unsustainable) outcomes, I argue, the logic on which they are produced must change. I conceptualize this change as a paradigmatic shift in knowledge-based innovation systems that becomes necessary to equip them with the requirements to foster sustainability transformations. To this end, I adduce the sustainable knowledge-based bioeconomy as an example of a new innovation paradigm. The knowledge base of innovation systems dedicated to sustainability is explored theoretically and empirically on a policy, an educational, and on a business level. The dissertation is composed of four studies published between 2017 and 2020. After an introduction to the topic and the presentation of the theoretical background, the first paper explores the paradigmatic changes necessary to align innovation systems to the normative implications of sustainability transformations. The types of knowledge required for transformations in the case of the shift towards a sustainable bioeconomy are dealt with in the second publication. The elaboration and refinement of the notion of dedicated knowledge provides a knowledge-theoretical basis for better informing policy makers aiming at the installation of a sustainable knowledge-based bioeconomy. In th ethird study, I analyze to what extent elements of transformative knowledge – one integral part of dedicated knowledge – are considered in the design of European academic bioeconomy curricula. The last paper spotlights the role of firms in contributing to a system-wide adoption of the dedication to sustainability. It closes an important gap between the macro-level of transformation theories and the powerful private actors contributing to its overall outcome from the micro-level. The final Chapter synthesizes and discusses the results of the dissertation’s publications by sketching the knowledge-based change of innovation paradigms that contribute to a transformation to sustainability. The results reveal that a reflection of dedicated transformation processes from a paradigmatic perspective offers theoretical insights that can and should inform public, academic, as well as corporate sustainability endeavors. The consideration of innovation paradigms prompts research to explicitly spell out the normative dimension of innovation processes in innovation systems. This is a decisive step to understanding and possibly informing actions aiming at deliberate change. As an example, I have framed the sustainable bioeconomy as a new paradigm that determines the rate and the direction of innovation in a dedicated innovation system. Once the sustainable bioeconomy paradigm is effective, I argue, it will spontaneously trigger a change in resources used without having it imposed from authorities. To get there, however, policies must take due consideration of the specific characteristics of the relevant knowledge flows, academia must be better trained to afford the required shift in perspectives and trigger transformation processes, and companies must reconsider the values they propose and deliver to their customers. The assemblage of publications spells out the theoretical underpinnings of the knowledge-based bioeconomy and its potential to serve as a new paradigm to spur sustainability transformations. More concretely, the dissertation reveals to what extent the role of knowledge and knowledge itself needs to be reconsidered and in which ways it must be expanded for achieving a systemic change towards more sustainable consumption and production patterns.
The role of institutions and networks in developing the bioeconomy : case studies from Ghana and Brazil
(2019) Scheiterle, Lilli; Birner, Regina
An increasing number of countries have begun putting focus on developing a bioeconomy strategy. The bioeconomy provides a new concept with the aim to design a sustainable economy, which is knowledge-based and based on the use of biological resources. This entails on the one hand higher production of biomass and on the other tighter networks of traditional, national and international institutions. Institutional networks are pivotal for the sustainable production and use of biological resources, as well for the development of innovative biological processes and principles to exploit the potential of biomass. This thesis explores three pivotal aspects needed to take advantage of the considerable untapped potential of the bioeconomy. The first case study aims to identify the determinants of the persisting low maize yields in northern Ghana, despite the introduction of a fertilizer subsidy program. The policy is largely regarded as an instrument to increase crop productivity and contribute to food security. The second empirical study explores the role of female-led market institutions in Ghana. Marketing is central to the development of the bioeconomy and as such, trader organizations have a key role to play the value chain. The third case study investigates, taking sugarcane as a case study example, how well Brazil, the world’s leader in sugarcane production, is positioned to realize the shift from a fossil-based to a bio-based economy (bioeconomy). The two case study countries Ghana and Brazil were chosen because of their comparable net primary productivity and pedo-climatic conditions, and because of their different stages in the realization of the bioeconomy. Two components are pivotal to the success of the bioeconomy: biomass and knowledge. Based on two case studies in Ghana, this thesis investigates first the efforts to increase maize productivity in the Guinea savanna and secondly explores the role of collective action groups as central actors to address the sustainability dimension of the bioeconomy. Brazil has successfully implemented pivotal aspects of the bioeconomy, especially in the sugarcane sector. For this reason it lends itself well to analyze the role of institutions and networks in the development of new processes and products. This study adopts a mixed methods approach to address three key aspects of the development of the bioeconomy: production, marketing, and the overall innovation system. Data collection and analysis included qualitative and quantitative methods from various disciplines. The findings are presented in three papers, which this cumulative thesis is composed of. The first paper adopts a multidisciplinary approach. A household survey, in-depth interviews, and focus group discussions served to gather data on the socio-economic challenges of maize production in the Guinea savanna. Additionally, soil and fertilizer samples were analyzed to identify natural constraints and potential governance challenges. The results from this paper show that both socio-economic and biophysical parameters contribute to an improved understanding of site-specific challenges, resulting in low maize productivity in the Guinea savanna of Ghana. The second paper explores the role of female-led market associations across regions, ethnicities, and market typologies throughout Ghana. For this study a qualitative approach was chosen with participant observation and in-depth open-ended interviews conducted with traders, both in and out of leadership positions. The results could not empirically confirm the prevailing discourse on the monopolizing power of female-led market associations. The study rather finds that traders’ collective action provides vital safety-net measures for asset-poor women engaging in risky market activity. However, the public perception is challenging female trader agencies. The third paper analyzes the role of institutions and focuses on the innovation networks in the sugarcane sector in Brazil. The study combines the novel concept of ‘biomass value-webs’ with the established National Innovation System concept. For data collection, in-depth interviews and Net-Maps as a participatory tool were applied. The results illustrate the importance of innovation networks for Brazil to become a front-runner in the future bioeconomy. In particular, it emphasizes the importance of integrating national and international private sector organizations, and the need for incentives to foster collaboration with knowledge institutions. Based on these findings, one can conclude that strengthening the efforts to tailor site-specific solutions that consider the inter-disciplinary nature of crop production, marketing and development of processes is crucial to the bioeconomy. Overall, more attention to innovation networks is required to master the challenges of the bioeconomy and take full advantage of its opportunities.
United we stand, divided we fall : essays on knowledge and its diffusion in innovation networks
(2019) Bogner, Kristina; Pyka, Andreas
Knowledge is a key resource, allowing firms to innovate and keep pace with national and international competitors. Therefore, the management of this resource within firms and innovation networks is of utmost importance. As the collection and generation of (new) knowledge gives such competitive advantage, there is a strong interest of firms and policy makers on how to foster the creation and diffusion of new knowledge. Within four studies, this doctoral thesis aims at extending the literature on knowledge diffusion performance by focussing on the effect of different network structures on diffusion performance as well as on knowledge types besides mere techno-economic knowledge. Study 1 analyses the effect of different structural disparities on knowledge diffusion by using an agent-based simulation model. It focuses on how different network structures influence knowledge diffusion performance. This study especially emphasizes the effect of an asymmetric degree distribution on knowledge diffusion performance. Study 1 complements previous research on knowledge diffusion by showing that (i) besides or even instead of the average path length and the average clustering coefficient, the (symmetry of) degree distribution influences knowledge diffusion. In addition, (ii) especially small, inadequately embedded agents seem to be a bottleneck for knowledge diffusion in this setting, and iii) the identified rather negative network structures on the macro level seem to result from the myopic linking strategies of the actors at the micro level, indicating a trade-off between ‘optimal’ structures at the network and at the actor level. Study 2 uses an agent-based simulation model to analyse the effect of different network properties on knowledge diffusion performance. In contrast to study 1, this study analyses this relationship in a setting in which knowledge is diffusing freely throughout an empirical formal R&D network as well as through four benchmark networks. In addition, the concept of cognitive distance and differences in learning between agents in the network are taken into account. Study 2 complements study 1 and further previous research on knowledge diffusion by showing that (i) the (asymmetry of) degree distribution and the distribution of links between actors in the network indeed influence knowledge diffusion performance to a large extend. In addition, (ii) the extent to which a skewed degree distribution dominates other network characteristics varies depending on the respective cognitive distance between agents. Study 3 analyses how so called dedicated knowledge can contribute to the transformation towards a sustainable, knowledge-based Bioeconomy. In this study, the concept of dedicated knowledge, i.e. besides mere-techno economic knowledge also systems knowledge, normative knowledge and transformative knowledge, is first introduced. Moreover, the characteristics of dedicated knowledge which are influencing knowledge diffusion performance are analysed and evaluated according to their importance and potential role for knowledge diffusion. In addition, it is analysed if and how current Bioeconomy innovation policies actually account for dedicated knowledge. This study complements previous research by taking a strong focus on different types of knowledge besides techno-economic knowledge (often overemphasized in policy approaches). It shows, that i) different types of knowledge necessarily need to be taken into account when creating policies for knowledge creation and diffusion, and ii) that especially systems knowledge so far has been insufficiently considered by current Bioeconomy policy approaches. Study 4 analyses the effect of different structural disparities on knowledge diffusion by deducing from theoretical considerations on network structures and diffusion performance. The study tries to answer whether the artificially generated network structures seem favourable for the diffusion of both mere techno-economic knowledge as well as dedicated knowledge. Study 4 especially complements previous research on knowledge diffusion by (i) analysing an empirical network over a long period of time, and (ii) by indicating a potential trade-off between structures favourable for the diffusion of mere techno-economic knowledge and those for the diffusion of other types of dedicated knowledge. Summing up, it is impossible to make general statements that allow for valid policy recommendations on network structures ‘optimal’ for knowledge diffusion. Without knowing the exact structures and context, politicians will hardly be able to influence network structures. Especially if we call for knowledge enabling transformations as the transformation towards a sustainable knowledge-based Bioeconomy, creating structures for the creation and diffusion of this knowledge is quite challenging and needs for the inclusion and close cooperation of many different actors on multiple levels.