Heyen U, Schüler D
Max-Planck-Institute for Marine Microbiology, Celsiusstrasse 1, 28359 Bremen, Germany.
Appl Microbiol Biotechnol. 2003 Jun;61(5-6):536-44. doi: 10.1007/s00253-002-1219-x. Epub 2003 Feb 20.
Media and growth conditions were optimized for the microaerobic cultivation of Magnetospirillum gryphiswaldense in flasks and in a fermentor, resulting in significantly increased cell and magnetosome yields, compared with earlier studies. A reliable method was established for the automatic control of low dissolved oxygen tensions (pO(2)) in the fermentor (oxystat). Growth and magnetosome formation by M. gryphiswaldense, M. magnetotacticum and Magnetospirillum sp. AMB-1 were studied at various oxygen concentrations. Despite differences in their growth responses with respect to oxygen, we found a clear correlation between pO(2) and magnetosome formation in all three Magnetospirillum strains. Magnetite biomineralization was induced only below a threshold value of 20 mbar O(2) and optimum conditions for magnetosome formation were found at a pO(2) of 0.25 mbar (1 bar = 10(5) Pa). A maximum yield of 6.3 mg magnetite l(-1) day(-1) was obtained with M. gryphiswaldense grown under oxystat conditions, which is the highest magnetosome productivity reported so far for a magnetotactic bacterium. In conclusion, the presented results provide the basis for large-scale cultivation of magnetospirilla under defined conditions.
对烧瓶和发酵罐中嗜格氏嗜磁螺菌的微需氧培养条件进行了优化，与早期研究相比，细胞和磁小体产量显著提高。建立了一种可靠的方法来自动控制发酵罐中的低溶解氧张力（pO₂）（氧稳定器）。研究了嗜格氏嗜磁螺菌、趋磁嗜磁菌和AMB-1嗜磁螺菌在不同氧浓度下的生长和磁小体形成。尽管它们对氧的生长反应存在差异，但我们发现所有三种嗜磁螺菌菌株中pO₂与磁小体形成之间存在明显的相关性。仅在20毫巴O₂的阈值以下诱导磁铁矿生物矿化，并且在pO₂为0.25毫巴（1巴 = 10⁵帕）时发现了磁小体形成的最佳条件。在氧稳定器条件下生长的嗜格氏嗜磁螺菌获得了最高产量为6.3毫克磁铁矿/升·天，这是迄今为止报道的趋磁细菌的最高磁小体生产率。总之，所呈现的结果为在特定条件下大规模培养嗜磁螺菌提供了基础。
