Browsing by Person "Grether, Jakob"

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    Bioprocess exploitation of microaerobic auto-induction using the example of rhamnolipid biosynthesis in Pseudomonas putida KT2440
    (2025) Grether, Jakob; Dittmann, Holger; Willems, Leon; Schmiegelt, Tabea; Benatto Perino, Elvio Henrique; Hubel, Philipp; Lilge, Lars; Hausmann, Rudolf; Grether, Jakob; Department of Bioprocess Engineering, Institute of Food Science and Biotechnology, University of Hohenheim, Fruwirthstr. 12, 70599, Stuttgart, Germany; Dittmann, Holger; Department of Bioprocess Engineering, Institute of Food Science and Biotechnology, University of Hohenheim, Fruwirthstr. 12, 70599, Stuttgart, Germany; Willems, Leon; Department of Bioprocess Engineering, Institute of Food Science and Biotechnology, University of Hohenheim, Fruwirthstr. 12, 70599, Stuttgart, Germany; Schmiegelt, Tabea; Department of Bioprocess Engineering, Institute of Food Science and Biotechnology, University of Hohenheim, Fruwirthstr. 12, 70599, Stuttgart, Germany; Benatto Perino, Elvio Henrique; Department of Bioprocess Engineering, Institute of Food Science and Biotechnology, University of Hohenheim, Fruwirthstr. 12, 70599, Stuttgart, Germany; Hubel, Philipp; Core Facility Hohenheim, Mass Spectrometry Core Facility, University of Hohenheim, Ottilie-Zeller-Weg 2, 70599, Stuttgart, Germany; Lilge, Lars; Department of Bioprocess Engineering, Institute of Food Science and Biotechnology, University of Hohenheim, Fruwirthstr. 12, 70599, Stuttgart, Germany; Hausmann, Rudolf; Department of Bioprocess Engineering, Institute of Food Science and Biotechnology, University of Hohenheim, Fruwirthstr. 12, 70599, Stuttgart, Germany
    Background: In biomanufacturing of surface-active agents, such as rhamnolipids, excessive foaming is a significant obstacle for the development of high-performing bioprocesses. The exploitation of the inherent tolerance of Pseudomonas putida KT2440, an obligate aerobic bacterium, to microaerobic conditions has received little attention so far. Here low-oxygen inducible promoters were characterized in biosensor strains and exploited for process control under reduction of foam formation by low aeration and stirring rates during biosynthesis of rhamnolipids. Results: In this study, homologous promoters of P. putida inducible under oxygen limitation were identified by non-targeted proteomic analyses and characterized by fluorometric methods. Proteomics indicated a remodeling of the respiratory chain and the regulation of stress-related proteins under oxygen limitation. Of the three promoters tested in fluorescent biosensor assays, the promoter of the oxygen-sensitive cbb3-type cytochrome c oxidase gene showed high oxygen-dependent controllability. It was used to control the gene expression of a heterologous di-rhamnolipid synthesis operon in an auto-inducing microaerobic two-phase bioprocess. By limiting the oxygen supply via low aeration and stirring rates, the bioprocess was clearly divided into a growth and a production phase, and sources of foam formation were reduced. Accordingly, rhamnolipid synthesis did not have to be controlled externally, as the oxygen-sensitive promoter was autonomously activated as soon as the oxygen level reached microaerobic conditions. A critical threshold of about 20% oxygen saturation was determined. Conclusions: Utilizing the inherent tolerance of P. putida to microaerobic conditions in combination with the application of homologous, low-oxygen inducible promoters is a novel and efficient strategy to control bioprocesses. Fermentation under microaerobic conditions enabled the induction of rhamnolipid production by low oxygen levels, while foam formation was limited by low aeration and stirring rates.
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    Structure elucidation and characterization of novel glycolipid biosurfactant produced by Rouxiella badensis DSM 100043T
    (2025) Harahap, Andre Fahriz Perdana; Conrad, Jürgen; Wolf, Mario; Pfannstiel, Jens; Klaiber, Iris; Grether, Jakob; Hiller, Eric; Vahidinasab, Maliheh; Salminen, Hanna; Treinen, Chantal; Perino, Elvio Henrique Benatto; Hausmann, Rudolf; Harahap, Andre Fahriz Perdana; Department of Bioprocess Engineering (150k), Institute of Food Science and Biotechnology, University of Hohenheim, Fruwirthstr. 12, 70599 Stuttgart, Germany; (A.F.P.H.); (J.G.); (E.H.); (M.V.); (E.H.B.P.); Conrad, Jürgen; Department of Organic Chemistry (130b), Institute of Chemistry, University of Hohenheim, Garbenstr. 30, 70599 Stuttgart, Germany; (J.C.); (M.W.); Wolf, Mario; Department of Organic Chemistry (130b), Institute of Chemistry, University of Hohenheim, Garbenstr. 30, 70599 Stuttgart, Germany; (J.C.); (M.W.); Pfannstiel, Jens; Mass Spectrometry Unit, Core Facility Hohenheim, University of Hohenheim, Ottilie-Zeller-Weg 2, 70599 Stuttgart, Germany; (J.P.); (I.K.); Klaiber, Iris; Mass Spectrometry Unit, Core Facility Hohenheim, University of Hohenheim, Ottilie-Zeller-Weg 2, 70599 Stuttgart, Germany; (J.P.); (I.K.); Grether, Jakob; Department of Bioprocess Engineering (150k), Institute of Food Science and Biotechnology, University of Hohenheim, Fruwirthstr. 12, 70599 Stuttgart, Germany; (A.F.P.H.); (J.G.); (E.H.); (M.V.); (E.H.B.P.); Hiller, Eric; Department of Bioprocess Engineering (150k), Institute of Food Science and Biotechnology, University of Hohenheim, Fruwirthstr. 12, 70599 Stuttgart, Germany; (A.F.P.H.); (J.G.); (E.H.); (M.V.); (E.H.B.P.); Vahidinasab, Maliheh; Department of Bioprocess Engineering (150k), Institute of Food Science and Biotechnology, University of Hohenheim, Fruwirthstr. 12, 70599 Stuttgart, Germany; (A.F.P.H.); (J.G.); (E.H.); (M.V.); (E.H.B.P.); Salminen, Hanna; Department of Food Material Science (150g), Institute of Food Science and Biotechnology, University of Hohenheim, Garbenstr. 21/25, 70599 Stuttgart, Germany;; Treinen, Chantal; Cellular Agriculture, TUM School of Life Sciences, Technical University of Munich, 85354 Freising, Germany;; Perino, Elvio Henrique Benatto; Department of Bioprocess Engineering (150k), Institute of Food Science and Biotechnology, University of Hohenheim, Fruwirthstr. 12, 70599 Stuttgart, Germany; (A.F.P.H.); (J.G.); (E.H.); (M.V.); (E.H.B.P.); Hausmann, Rudolf; Department of Bioprocess Engineering (150k), Institute of Food Science and Biotechnology, University of Hohenheim, Fruwirthstr. 12, 70599 Stuttgart, Germany; (A.F.P.H.); (J.G.); (E.H.); (M.V.); (E.H.B.P.); Serianni, Anthony S.
    Microbial biosurfactants have become increasingly attractive as promising ingredients for environmentally friendly products. The reasons for this are their generally good performance and biodegradability, low toxicity, production from renewable raw materials, and benefits for the environment perceived by consumers. In this study, we investigated the chemical structure and properties of a novel glycolipid from a new biosurfactant-producing strain, Rouxiella badensis DSM 100043 T . Bioreactor cultivation was performed at 30 °C and pH 7.0 for 28 h using 15 g/L glycerol as a carbon source. The glycolipid was successfully purified from the ethyl acetate extract of the supernatant using medium pressure liquid chromatography (MPLC). The structure of the glycolipid was determined by one- and two-dimensional ( 1 H and 13 C) nuclear magnetic resonance (NMR) and confirmed by liquid chromatography electrospray ionization mass spectrometry (LC-ESI/MS). NMR analysis revealed the hydrophilic moiety as a glucose molecule and the hydrophobic moieties as 3-hydroxy-5-dodecenoic acid and 3-hydroxydecanoic acid, which are linked with the glucose by ester bonds at the C2 and C3 positions. Surface tension measurement with tensiometry indicated that the glucose–lipid could reduce the surface tension of water from 72.05 mN/m to 24.59 mN/m at 25 °C with a very low critical micelle concentration (CMC) of 5.69 mg/L. Moreover, the glucose–lipid demonstrated very good stability in maintaining emulsification activity at pH 2–8, a temperature of up to 100 °C, and a NaCl concentration of up to 15%. These results show that R. badensis DSM 100043 T produced a novel glycolipid biosurfactant with excellent surface-active properties, making it promising for further research or industrial applications.