Department of Chemical Engineering (BK21 FOUR Integrated Engineering Program), Kyung Hee University, Yongin-si, Gyeonggi-do, Republic of Korea.
Department of Chemical and Biomolecular Engineering, Sogang University, Seoul, Republic of Korea.
PLoS One. 2023 May 10;18(5):e0284846. doi: 10.1371/journal.pone.0284846. eCollection 2023.
Biodegradable polyhydroxybutyrate (PHB) can be produced from methane by some type II methanotroph such as the genus Methylocystis. This study presents the comparative genomic analysis of a newly isolated methanotroph, Methylocystis sp. MJC1 as a biodegradable PHB-producing platform strain. Methylocystis sp. MJC1 accumulates up to 44.5% of PHB based on dry cell weight under nitrogen-limiting conditions. To facilitate its development as a PHB-producing platform strain, the complete genome sequence of Methylocystis sp. MJC1 was assembled, functionally annotated, and compared with genomes of other Methylocystis species. Phylogenetic analysis has shown that Methylocystis parvus to be the closest species to Methylocystis sp. MJC1. Genome functional annotation revealed that Methylocystis sp. MJC1 contains all major type II methanotroph biochemical pathways such as the serine cycle, EMC pathway, and Krebs cycle. Interestingly, Methylocystis sp. MJC1 has both particulate and soluble methane monooxygenases, which are not commonly found among Methylocystis species. In addition, this species also possesses most of the RuMP pathway reactions, a characteristic of type I methanotrophs, and all PHB biosynthetic genes. These comparative analysis would open the possibility of future practical applications such as the development of organism-specific genome-scale models and application of metabolic engineering strategies to Methylocystis sp. MJC1.
可生物降解的聚羟基丁酸酯 (PHB) 可以由某些类型 II 甲烷营养菌，如甲基球菌属，从甲烷中生产。本研究介绍了一种新分离的甲烷营养菌，甲基球菌属 MJC1 的比较基因组分析，作为可生物降解 PHB 生产平台菌株。在氮限制条件下，甲基球菌属 MJC1 可根据干重积累高达 44.5%的 PHB。为了促进其作为 PHB 生产平台菌株的发展，组装、功能注释并比较了甲基球菌属 MJC1 的完整基因组序列与其他甲基球菌属物种的基因组。系统发育分析表明，小甲基球菌与甲基球菌属 MJC1 最为接近。基因组功能注释表明，甲基球菌属 MJC1 包含所有主要的 II 型甲烷营养菌生化途径，如丝氨酸循环、EMC 途径和三羧酸循环。有趣的是，甲基球菌属 MJC1 同时具有颗粒型和可溶性甲烷单加氧酶，这在甲基球菌属中并不常见。此外，该物种还具有大多数 RuMP 途径反应，这是 I 型甲烷营养菌的特征，以及所有 PHB 生物合成基因。这些比较分析为未来的实际应用开辟了可能性，例如开发特定于生物体的基因组规模模型和应用代谢工程策略到甲基球菌属 MJC1。
