In recent years, household biogas technology has been widely used in rural areas in China. Understanding the co-occurrence relationships of core biogas microbiota for household use and their relationship with environmental factors will help improve the efficiency and stability of household biogas fermentation systems.
Researchers at the Chengdu Institute of Biology, Chinese Academy of Sciences, Li Xiangzhen's research group Yan Junpeng and Li Jiabao used high-throughput sequencing methods to investigate microbial communities in 43 biogas samples from different household biogas digesters in 8 provinces. The study found that Clostridium, Clostridium XI, Syntrophomonas, Cloacibacillus and other 10 genera constitute the core flora.
In terms of Beta diversity, the microbial communities of these 43 samples were divided into two distinct groups: the lower diversity of Cluster I, mainly Clostridium, ammonium nitrogen and COD as the main influence factors; Cluster II was Spirochaetes, Bacteroidales and Clostridia are the dominant flora and are rich in reciprocal bacteria and methanogens. Ammonium nitrogen, pH, and phosphate concentrations are the main influence factors. The network analysis based on the flora correlation shows that the microbial network of biogas slurry can be divided into several functional modules: Cluster I is mainly composed of primary fermentation module (driven by Clostridium) and acetic acid-based methanogenic module; Cluster II is much more complex, mainly Hydrogen and acetic acid two methanogenic modules and a primary fermentation module (driven jointly by Spirochaetes, Bacteroidales, Clostridia) consist of ammonium nitrogen concentration.
The study reveals the prevalence of co-occurrences of core bacterial populations in household biogas systems and recognizes the importance of microbial functional redundancy in resisting environmental stress and maintaining fermentation efficiency.
The results of the study were published in the bioenergy for biofuels.
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