Biotechnology Bulletin ›› 2025, Vol. 41 ›› Issue (6): 355-366.doi: 10.13560/j.cnki.biotech.bull.1985.2024-1180

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Effect of Carbon Source in Methanogenic Communities Regulation and Methane Production Capacity

AN Miao-miao(), LIN Xiang-hao, LIANG Rui-na, ZHAO Guo-zhu()   

  1. Beijing Key Laboratory of Food Processing and Safety in Forestry, College of Biological Sciences and Technology, Beijing Forestry University, Beijing 100083
  • Received:2024-12-05 Online:2025-06-26 Published:2025-06-30
  • Contact: ZHAO Guo-zhu E-mail:anmiao315418@163.com;zhaogz@bjfu.edu.cn

Abstract:

Objective Methanogens play a pivotal role in methanogenesis during anaerobic digestion. To obtain an efficient methanogenic microbial community, the regulatory effects of different carbon sources on the methane production potential, methanogen abundance, and microbial community structure were investigated. Method Three distinct carbon source culture media (Group A: CH3COONa and CH3OH;Group B: CH3COONa; Group C: CH3COONa and HCOONa) were designed to enrich methanogenic communities by inoculating with anaerobic digestion liquid from kitchen waste (FW) and activated sludge suspension (SS). The performance and diversity composition of methanogenic microbial community were analyzed using gas chromatography, real-time quantitative PCR (qPCR), fluorescence microscopy, and amplicon sequencing. Result The microbial communities enriched by carbon sources A, B, and C demonstrated a descending order of methane yield when inoculated with the same inoculum. Group 1A-2 achieved the highest cumulative methane yield over 49 d, with a methane yield of 35.9 mL per gram of available carbon (C) in a unit volume (L) of culture medium. The copy number of mcrA gene and fluorescence microscopy observations indicated a successive decrease in methanogen abundance in communities enriched by carbon sources A, B, and C. Specifically, carbon source A enriched methylotrophic methanogens, while carbon source B significantly boosted the relative abundance of aceticlastic Methanothrix compared to the other groups. Carbon source C notably enhanced the relative abundance of hydrogenotrophic methanogens. Conclusion The type of carbon source significantly influence the diversity, richness, and community structure of methanogens and bacteria in the enriched microbial communities. The microbial communities enriched with CH3COONa and CH3OH (Group A) showed the highest methanogen abundance, mainly including Methanothrix, Methanoculleus, Methanomethylovorans, Candidatus Methanoplasmaand Methanosarcina, and demonstrated the highest methanogenic capacity. Carbon source A promotes methane (CH₄) production by enriching syntrophic bacteria, balancing the metabolic pathway distribution of methanogens, and facilitating direct interspecies electron transfer (DIET).

Key words: anaerobic culture, methanogens, real-time quantitative PCR, fluorescence observation, amplicon sequencing