Colpa Dana I, Zhou Wen, Wempe Jan Pier, Tamis Jelmer, Stuart Marc C A, Krooneman Janneke, Euverink Gert-Jan W
Products and Processes for Biotechnology Group, Engineering and Technology Institute Groningen, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands.
Paques Technology B.V., Tjalke de Boerstrjitte 24, 8561 EL Balk, The Netherlands.
Bioengineering (Basel). 2020 Feb 21;7(1):19. doi: 10.3390/bioengineering7010019.
Polyhydroxyalkanoates (PHAs) form a highly promising class of bioplastics for the transition from fossil fuel-based plastics to bio-renewable and biodegradable plastics. Mixed microbial consortia (MMC) are known to be able to produce PHAs from organic waste streams. Knowledge of key-microbes and their characteristics in PHA-producing consortia is necessary for further process optimization and direction towards synthesis of specific types of PHAs. In this study, a PHA-producing mixed microbial consortium (MMC) from an industrial pilot plant was characterized and further enriched on acetate in a laboratory-scale selector with a working volume of 5 L, and 16S-rDNA microbiological population analysis of both the industrial pilot plant and the 5 L selector revealed that the most dominant species within the population is MZ1T, a Gram-negative beta-proteobacterium belonging to the order of the Rhodocyclales. The relative abundance of this species increased from 24 to 40% after two months of enrichment in the selector-system, indicating a competitive advantage, possibly due to the storage of a reserve material such as PHA. First experiments with MZ1T showed multiple intracellular granules when grown in pure culture on a growth medium with a C:N ratio of 10:1 and acetate as a carbon source. Nuclear magnetic resonance (NMR) analyses upon extraction of PHA from the pure culture confirmed polyhydroxybutyrate production by MZ1T.
聚羟基脂肪酸酯（PHA）是一类极具前景的生物塑料，可助力从化石燃料基塑料向生物可再生及可生物降解塑料的转变。已知混合微生物群落（MMC）能够利用有机废物流生产PHA。了解PHA生产群落中的关键微生物及其特性，对于进一步优化工艺以及合成特定类型PHA的方向指引至关重要。在本研究中，对来自一家工业中试工厂的PHA生产混合微生物群落（MMC）进行了表征，并在一个工作体积为5升的实验室规模选择器中用乙酸盐进一步富集。对工业中试工厂和5升选择器进行的16S - rDNA微生物种群分析表明，该种群中最主要的物种是MZ1T，它是一种革兰氏阴性β - 变形菌，属于红环菌目。在选择器系统中富集两个月后，该物种的相对丰度从24%增加到了40%，这表明它具有竞争优势，可能是由于储存了诸如PHA之类的储备物质。对MZ1T进行的首次实验表明，当它在碳氮比为10:1且以乙酸盐作为碳源的生长培养基上进行纯培养时，细胞内会出现多个颗粒。从纯培养物中提取PHA后进行的核磁共振（NMR）分析证实了MZ1T能够产生聚羟基丁酸酯。
