Different Interspecies Electron Transfer Patterns during Mesophilic and Thermophilic Syntrophic Propionate Degradation in Chemostats

• Published in: Microbial ecology Vol. 80; no. 1; pp. 120 - 132
• Main Authors: Chen, Ya-Ting, Zeng, Yan, Wang, Hui-Zhong, Zheng, Dan, Kamagata, Yoichi, Narihiro, Takashi, Nobu, Masaru Konishi, Tang, Yue-Qin
• Format: Journal Article
• Language: English
• Published: New York Springer Science + Business Media 01.07.2020; Springer US; Springer Nature B.V
• Subjects: Alternative energy sources; Anaerobic digestion; Anaerobic treatment; Bacteria; biochemical pathways; Biodegradation; Biomedical and Life Sciences; Bioreactors; By products; Carbon; Carbon dioxide; Chemostats; Consortia; Degradation; Ecological effects; Ecology; Electron transfer; Electrons; Energy conservation; ENVIRONMENTAL MICROBIOLOGY; Geoecology/Natural Processes; hydrogen; Intermediates; Life Sciences; Metabolic pathways; Metabolism; Metabolites; Metagenomics; methane; Methanoculleus; Methanogenic bacteria; methanogens; Microbial activity; microbial communities; Microbial Ecology; Microbiology; Microorganisms; Nature Conservation; Niches; Organic wastes; oxidants; Oxidation; Oxidizing agents; Oxidoreductions; Phylogeny; Propionic acid; Smithella; Symbionts; Syntrophobacter; Syntrophomonas; Temperature; Thermophilic microorganisms; transcriptomics; Water Quality/Water Pollution; Metagenomics; formate transfer; Energy conservation; Metatranscriptomics; Anaerobic digestion; Propionate degradation; Interspecies H; Interspecies H2/formate transfer
• ISSN: 0095-3628; 1432-184X; 1432-184X
• DOI: 10.1007/s00248-020-01485-x

Propionate is one of the major intermediates in anaerobic digestion of organic waste to CO₂ and CH₄. 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 H₂ transfer played a major role, and phylogenetically and metabolically diverse H₂-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.