Products and Processes for Biotechnology, Engineering and Technology Institute Groningen, Faculty of Science and Engineering, University of Groningen, Groningen, the Netherlands.
Wetsus, European Centre of Excellence for Sustainable Water Technology, Leeuwarden, the Netherlands.
Sci Total Environ. 2022 Mar 10;811:152341. doi: 10.1016/j.scitotenv.2021.152341. Epub 2021 Dec 15.
Growth conditions have been frequently studied in optimizing polyhydroxybutyrate (PHB) production, while few studies were performed to unravel the dynamic mixed microbial consortia (MMCs) in the process. In this study, the relationship between growth conditions (C/N ratios and pH) and the corresponding key-microbes were identified and monitored during PHB accumulation. The highest PHB level (70 wt% of dry cell mass) was obtained at pH 9, C/N 40, and acetic acid 10 g/L. Linking the dominant genera with the highest point of PHB accumulation, Thauera was the most prevalent species in all MMCs of pH 9, except when a C/N ratio of 1 was applied. Notably, dominant bacteria shifted at pH 7 (C/N 10) from Thauera (0 h) to Paracoccus, and subsequently to Alcaligenes following the process of PHB accumulation and consumption. Further understanding of the relationship between the structure of the microbial community and the performance will be beneficial for regulating and obtaining high PHB accumulation within an MMC. Our study illustrates the impact of C/N ratios and pH on microbial prevalence and PHB production levels using a mixed microbial starter culture. This knowledge will broaden industrial perspectives for regulating high PHB production and timely harvesting.
在优化聚羟基丁酸酯 (PHB) 生产的过程中,经常研究生长条件,而很少有研究来揭示该过程中动态混合微生物群落 (MMC)。在这项研究中,确定了生长条件(C/N 比和 pH 值)与 PHB 积累过程中相应关键微生物之间的关系,并对其进行了监测。在 pH 值为 9、C/N 为 40 和乙酸 10 g/L 的条件下,可获得最高 PHB 水平(占干细胞质量的 70wt%)。将优势属与 PHB 积累的最高点联系起来,除了 C/N 比为 1 时,Thauera 是所有 pH 值为 9 的 MMC 中最普遍的物种。值得注意的是,在 PHB 积累和消耗过程中,pH 值为 7(C/N 为 10)时的优势细菌从 Thauera(0h)转变为 Paracoccus,随后转变为 Alcaligenes。进一步了解微生物群落结构与性能之间的关系将有助于调节和获得 MMC 中高 PHB 积累。我们的研究使用混合微生物启动培养物说明了 C/N 比和 pH 值对微生物流行和 PHB 生产水平的影响。这一知识将拓宽工业视角,以调节高 PHB 生产和及时收获。