An automated oxystat fermentation regime for microoxic cultivation of Magnetospirillum gryphiswaldense

Microbial Cell Factories

Anna S. Schenk¹  Valérie Jérôme²  Ruth Freitag²  Cornelius N. Riese³  René Uebe³  Dirk Schüler³  Sabine Rosenfeldt⁴ 

[1] Bavarian Polymer Institute (BPI), University of Bayreuth, Universitätsstraße 30, 95447, Bayreuth, Germany;Physical Chemistry - Colloidal Systems, University of Bayreuth, Universitätsstraße 30, 95447, Bayreuth, Germany;Chair for Process Biotechnology, University of Bayreuth, Universitätsstraße 30, 95447, Bayreuth, Germany;Department of Microbiology, University of Bayreuth, Universitätsstraße 30, 95447, Bayreuth, Germany;Physical Chemistry I, University of Bayreuth, Universitätsstraße 30, 95447, Bayreuth, Germany;Bavarian Polymer Institute (BPI), University of Bayreuth, Universitätsstraße 30, 95447, Bayreuth, Germany;

关键词: Magnetosomes;    Magnetospirillum gryphiswaldense;    Oxystat fermentation;    Magnetosome biomineralization;   

DOI  :  10.1186/s12934-020-01469-z

来源: Springer

【 摘 要 】

BackgroundMagnetosomes produced by magnetotactic bacteria represent magnetic nanoparticles with unprecedented characteristics. However, their use in many biotechnological applications has so far been hampered by their challenging bioproduction at larger scales.ResultsHere, we developed an oxystat batch fermentation regime for microoxic cultivation of Magnetospirillum gryphiswaldense in a 3 L bioreactor. An automated cascade regulation enabled highly reproducible growth over a wide range of precisely controlled oxygen concentrations (1–95% of air saturation). In addition, consumption of lactate as the carbon source and nitrate as alternative electron acceptor were monitored during cultivation. While nitrate became growth limiting during anaerobic growth, lactate was the growth limiting factor during microoxic cultivation. Analysis of microoxic magnetosome biomineralization by cellular iron content, magnetic response, transmission electron microscopy and small-angle X-ray scattering revealed magnetosomal magnetite crystals were highly uniform in size and shape.ConclusionThe fermentation regime established in this study facilitates stable oxygen control during culturing of Magnetospirillum gryphiswaldense. Further scale-up seems feasible by combining the stable oxygen control with feeding strategies employed in previous studies. Results of this study will facilitate the highly reproducible laboratory-scale bioproduction of magnetosomes for a diverse range of future applications in the fields of biotechnology and biomedicine.

【 授权许可】

CC BY