College of Architecture and Environment, Sichuan University, No. 24, South Section 1, First Ring Road, Chengdu, 610065, Sichuan, China.
Institute for Disaster Management and Reconstruction, Sichuan University-Hong Kong Polytechnic University, Chengdu, 610207, China.
Microb Ecol. 2020 Jul;80(1):120-132. doi: 10.1007/s00248-020-01485-x. Epub 2020 Jan 25.
Propionate is one of the major intermediates in anaerobic digestion of organic waste to CO and CH. In methanogenic environments, propionate is degraded through a mutualistic interaction between symbiotic propionate oxidizers and methanogens. Although temperature heavily influences the microbial ecology and performance of methanogenic processes, its effect on syntrophic interaction during propionate degradation remains poorly understood. In this study, metagenomics and metatranscriptomics were employed to compare mesophilic and thermophilic propionate degradation communities. Mesophilic propionate degradation involved multiple syntrophic organisms (Syntrophobacter, Smithella, and Syntrophomonas), pathways, interactions, and preference toward formate-based electron transfer to methanogenic partners (i.e., Methanoculleus). In thermophilic propionate degradation, one syntrophic organism predominated (Pelotomaculum), interspecies H transfer played a major role, and phylogenetically and metabolically diverse H-oxidizing methanogens were present (i.e., Methanoculleus, Methanothermobacter, and Methanomassiliicoccus). This study showed that microbial interactions, metabolic pathways, and niche diversity are distinct between mesophilic and thermophilic microbial communities responsible for syntrophic propionate degradation.
丙酸是有机废物在厌氧消化过程中产生的主要中间产物之一，可进一步转化为 CO 和 CH。在产甲烷环境中，丙酸通过共生丙酸氧化菌和产甲烷菌之间的互利共生相互作用进行降解。尽管温度会强烈影响产甲烷过程的微生物生态和性能，但它对丙酸降解过程中协同作用的影响仍知之甚少。在这项研究中，我们采用宏基因组学和宏转录组学技术来比较中温和高温条件下的丙酸降解群落。中温丙酸降解涉及多种协同生物（Syntrophobacter、Smithella 和 Syntrophomonas）、途径、相互作用以及对基于甲酸盐的电子转移到产甲烷菌（即 Methanoculleus）的偏好。在高温丙酸降解中，一种协同生物（Pelotomaculum）占主导地位，种间 H 转移起主要作用，并且存在具有不同进化和代谢特性的 H 氧化产甲烷菌（即 Methanoculleus、Methanothermobacter 和 Methanomassiliicoccus）。本研究表明，负责协同丙酸降解的中温和高温微生物群落之间的微生物相互作用、代谢途径和生态位多样性存在明显差异。
