Browsing by Subject "Amino acids"

Now showing 1 - 5 of 5

Challenges of green production of 2,5‐furandicarboxylic acid from bio‐derived 5‐hydroxymethylfurfural: Overcoming deactivation by concomitant amino acids
(2022) Neukum, Dominik; Baumgarten, Lorena; Wüst, Dominik; Sarma, Bidyut Bikash; Saraçi, Erisa; Kruse, Andrea; Grunwaldt, Jan‐Dierk
The oxidation of 5‐hydroxymethylfurfural (HMF) to 2,5‐furandicarboxylic acid (FDCA) is highly attractive as FDCA is considered as substitute for the petrochemically derived terephthalic acid. There are only few reports on the direct use of unrefined HMF solutions from biomass resources and the influence of remaining constituents on the catalytic processes. In this work, the oxidation of HMF in a solution as obtained from hydrolysis and dehydration of saccharides in chicory roots was investigated without intermediate purification steps. The amount of base added to the solution was critical to increase the FDCA yield. Catalyst deactivation occurred and was attributed to poisoning by amino acids from the bio‐source. A strong influence of amino acids on the catalytic activity was found for all supported Au, Pt, Pd, and Ru catalysts. A supported AuPd(2 : 1)/C alloy catalyst exhibited both superior catalytic activity and higher stability against deactivation by the critical amino acids.
A comprehensive characterization of agronomic and end-use quality phenotypes across a quinoa world core collection
(2023) Craine, Evan B.; Davies, Alathea; Packer, Daniel; Miller, Nathan D.; Schmöckel, Sandra M.; Spalding, Edgar P.; Tester, Mark; Murphy, Kevin M.
Quinoa (Chenopodium quinoa Willd.), a pseudocereal with high protein quality originating from the Andean region of South America, has broad genetic variation and adaptability to diverse agroecological conditions, contributing to the potential to serve as a global keystone protein crop in a changing climate. However, the germplasm resources currently available to facilitate quinoa expansion worldwide are restricted to a small portion of quinoa’s total genetic diversity, in part because of day-length sensitivity and issues related to seed sovereignty. This study aimed to characterize phenotypic relationships and variation within a quinoa world core collection. The 360 accessions were planted in a randomized complete block design with four replicates in each of two greenhouses in Pullman, WA during the summer of 2018. Phenological stages, plant height, and inflorescence characteristics were recorded. Seed yield, composition, thousand seed weight, nutritional composition, shape, size, and color were measured using a high-throughput phenotyping pipeline. Considerable variation existed among the germplasm. Crude protein content ranged from 11.24% to 17.81% (fixed at 14% moisture). We found that protein content was negatively correlated with yield and positively correlated with total amino acid content and days to harvest. Mean essential amino acids values met adult daily requirements but not leucine and lysine infant requirements. Yield was positively correlated with thousand seed weight and seed area, and negatively correlated with ash content and days to harvest. The accessions clustered into four groups, with one-group representing useful accessions for long-day breeding programs. The results of this study establish a practical resource for plant breeders to leverage as they strategically develop germplasm in support of the global expansion of quinoa.
Drying behavior and effect of drying temperatures on cyanide, bioactive compounds, and quality of dried cassava leaves
(2025) Chaiareekitwat, Sawittree; Nagle, Marcus; Mahayothee, Busarakorn; Khuwijitjaru, Pramote; Rungpichayapichet, Parika; Latif, Sajid; Müller, Joachim; Chaiareekitwat, Sawittree; Institute of Agricultural Engineering, Tropics and Subtropics Group, University of Hohenheim, 70599 Stuttgart, Germany; (S.C.); (S.L.); Nagle, Marcus; Agricultural Research and Development Program, Central State University, Wilberforce, OH 45384, USA;; Mahayothee, Busarakorn; Department of Food Technology, Faculty of Engineering and Industrial Technology, Silpakorn University, Nakhon Pathom 73000, Thailand; (P.K.); (P.R.); Khuwijitjaru, Pramote; Department of Food Technology, Faculty of Engineering and Industrial Technology, Silpakorn University, Nakhon Pathom 73000, Thailand; (P.K.); (P.R.); Rungpichayapichet, Parika; Department of Food Technology, Faculty of Engineering and Industrial Technology, Silpakorn University, Nakhon Pathom 73000, Thailand; (P.K.); (P.R.); Latif, Sajid; Institute of Agricultural Engineering, Tropics and Subtropics Group, University of Hohenheim, 70599 Stuttgart, Germany; (S.C.); (S.L.); Müller, Joachim; Institute of Agricultural Engineering, Tropics and Subtropics Group, University of Hohenheim, 70599 Stuttgart, Germany; (S.C.); (S.L.); Medana, Claudio
In this study, the drying behavior and quality of the dried leaves of cassava ( Manihot esculenta Crantz) of the ‘Rayong 5’ cultivar from Thailand were investigated. An increase in the drying temperature resulted in an increased drying rate and a reduction in drying time. The Page model provided the best fit for describing the drying characteristics of cassava leaves, with the entire drying process occurring in the falling rate period. The results showed that cyanide content was sensitive to high temperatures, with drying at 80 °C being the most effective method for toxin elimination. Prolonged drying periods lead to the degradation of vitamin C. Drying cassava leaves at 50–80 °C did not significantly affect β–carotene levels. However, lutein, chlorophyll– a , and chlorophyll– b were reduced after drying. The drying processes did not change the crude proteins content but increased the levels of histidine, alanine, and aspartic acid. In this study, high-temperature, short-time drying was identified as the optimal condition for detoxification, maintaining nutrients, and preserving the color of dried cassava leaves.
Factors influencing proteolysis and protein utilization in the intestine of pigs: A review
(2021) Kurz, Alina; Seifert, Jana
Pigs are among the most important farm animals for meat production worldwide. In order to meet the amino acid requirements of the animals, pigs rely on the regular intake of proteins and amino acids with their feed. Unfortunately, pigs excrete about two thirds of the used protein, and production of pork is currently associated with a high emission of nitrogen compounds resulting in negative impacts on the environment. Thus, improving protein efficiency in pigs is a central aim to decrease the usage of protein carriers in feed and to lower nitrogen emissions. This is necessary as the supply of plant protein sources is limited by the yield and the cultivable acreage for protein plants. Strategies to increase protein efficiency that go beyond the known feeding options have to be investigated considering the characteristics of the individual animals. This requires a deep understanding of the intestinal processes including enzymatic activities, capacities of amino acid transporters and the microbiome. This review provides an overview of these physiological factors and the respective analyses methods.
Metabolic rewiring compensates for the loss of amino acid biosynthesis in Bacillus subtilis
(2024) Yousef Mardoukhi, Mohammad Saba; Commichau, Fabian M.
Amino acids are considered as some of the earliest organic molecules to form on Earth. Serving as the building blocks of proteins, they are intricately connected to nearly every life process. Therefore, amino acid metabolism needs to be precisely regulated in any living organism. Amino acid metabolism includes the biochemical pathways responsible for the synthesis, degradation, and utilization of amino acids. Most of the bacteria, particularly the Gram-positive model bacterium Bacillus subtilis, have the capability to synthesize all proteinogenic amino acids or, if available, import them from the environment. Throughout evolution, different metabolic pathways have emerged to maintain metabolites level inside the cells. Some biosynthetic pathways are unknown as they are not primary routes or are typically inactive under normal conditions. However, they may become active under specific circumstances. Two very important pathways, previously not known to be substituted by alternative routes, involve de novo biosynthesis of glutamate, which is an essential amino group donor in every cell. Many bacteria can synthesize glutamate using a NADPH + H+-dependent glutamate dehydrogenase (GDH). Alternatively, glutamate can be produced by the combined action of the ATP-dependent glutamine synthetase (GS) and the NADPH + H+-dependent glutamate synthase (GOGAT). B. subtilis only employs the GS-GOGAT pathway for de novo synthesis of glutamate. In the context of this work, it was shown that a B. subtilis deficient for the GS-GOGAT pathway may employ the aspartase AnsB and aspartate transaminase AspB for the synthesis of glutamate in biologically significant amounts. Genetic analyses revealed that the aspartase AnsB converts ammonium and the tricarboxylic acid cycle intermediate fumarate to aspartate. Subsequently, the aspartate transaminase AspB transfers the amino group from aspartate to α-ketoglutarate, resulting in the production of L-glutamate and oxaloacetate. This observation challenges the well-established point of view of whether the GS-GOGAT-dependent pathway is indeed the only route for de novo synthesis of glutamate in nature. It was also set out to explore which amino acids could serve as the sole sources of carbon and nitrogen in the background of a B. subtilis strain that is a genetically stable glutamate auxotroph. The aim was to understand the conversion of the amino acids into glutamate and further to α-ketoglutarate, a reaction that is facilitated by the enzymatic activity of the GDHs RocG/GudB. It turned out that some of the amino acids are toxic for B. subtilis. However, B. subtilis can quickly develop resistance by the acquisition of mutations that result in reduced and enhanced amino acid uptake and export, respectively. Moreover, the toxicity of some amino acids may be reduced by increased degradation of glutamate. Furthermore, with focus on the toxicity of asparagine, it could be demonstrated that AimA, which has been characterized as a general amino acid importer, serves as a low affinity asparagine transporter in B. subtilis. Finally, AzlCD, which was previously described as an exporter for histidine and branched-chain amino acids, also exports asparagine. Thus, B. subtilis can adapt to amino acid toxicity in various ways.