Department of Bioprocess Engineering (150 k), Institute of Food Science and Biotechnology (150), University of Hohenheim, Fruwirthstr. 12, 70599, Stuttgart, Germany.
Appl Microbiol Biotechnol. 2021 May;105(10):4141-4151. doi: 10.1007/s00253-021-11330-x. Epub 2021 May 15.
Bacillus subtilis 3NA is a strain capable of reaching high cell densities. A surfactin producing sfp variant of this strain, named JABs32, was utilized in fed-batch cultivation processes. Both a glucose and an ammonia solution were fed to set a steady growth rate μ of 0.1 h. In this process, a cell dry weight of up to 88 g L was reached after 38 h of cultivation, and surfactin titers of up to 26.5 g L were detected in this high cell density fermentation process, achieving a Y value of 0.23 g g as well as a q of 0.007 g g h. In sum, a 21-fold increase in surfactin titer was obtained compared with cultivations in shake flasks. In contrast to fed-batch operations using Bacillus subtilis JABs24, an sfp variant derived from B. subtilis 168, JABs32, reached an up to fourfold increase in surfactin titers using the same fed-batch protocol. Additionally, a two-stage feed process was established utilizing strain JABs32. Using an optimized mineral salt medium in this high cell density fermentation approach, after 31 h of cultivation, surfactin titers of 23.7 g L were reached with a biomass concentration of 41.3 g L, thus achieving an enhanced Y value of 0.57 g g as well as a q of 0.018 g g h. The mutation of spo0A locus and an elongation of AbrB in the strain utilized in combination with a high cell density fed-batch process represents a promising new route for future enhancements on surfactin production. KEY POINTS: • Utilization of a sporulation deficient strain for fed-batch operations • High cell density process with Bacillus subtilis for lipopeptide production was established • High titer surfactin production capabilities confirm highly promising future platform strain.
枯草芽孢杆菌 3NA 是一种能够达到高细胞密度的菌株。该菌株的一个表面活性剂产生 sfp 变体，命名为 JABs32，被用于分批补料培养过程。在该过程中，葡萄糖和氨溶液均被补料以设定稳定的生长速率 μ 为 0.1 h。在这个过程中，经过 38 h 的培养，达到了高达 88 g/L 的细胞干重，并且在这个高密度发酵过程中检测到了高达 26.5 g/L 的表面活性剂产量，实现了 0.23 g/g 的 Y 值和 0.007 g/g h 的 q 值。总的来说，与摇瓶培养相比，表面活性剂产量提高了 21 倍。与使用枯草芽孢杆菌 JABs24 的分批补料操作相反，JABs32，一种源自枯草芽孢杆菌 168 的 sfp 变体，使用相同的分批补料方案，表面活性剂产量提高了四倍。此外，使用菌株 JABs32 建立了两阶段进料过程。在这种高密度发酵方法中使用优化的无机盐培养基，经过 31 h 的培养，达到了 23.7 g/L 的表面活性剂产量，生物质浓度为 41.3 g/L，从而实现了增强的 0.57 g/g 的 Y 值和 0.018 g/g h 的 q 值。利用突变的 spo0A 基因座和伸长的 AbrB 菌株与高密度分批补料过程相结合，代表了未来表面活性剂生产增强的有前途的新途径。关键点：• 利用孢子缺陷菌株进行分批补料操作• 建立枯草芽孢杆菌高密度分批补料过程用于生产脂肽• 高产量表面活性剂生产能力证实了极具前景的未来平台菌株。
