Effects of different functional strains on key metabolic pathways of methanogenesis in the domestic waste fermentation reactor

Highlights: • Increasing the reaction rate in the hydrolysis stage can promote methane production. • P.acetatigen and B.theaiotaomicron promote to the bioenergy, especially methane. • Tax4Fun revealed the pathway of methane produced by landfill is mainly CO₂ reduction. The improvement of landfill gas utilization efficiency will produce considerable environmental and economic benefits. This study simulated the fermentation of domestic waste through the addition of functional strains. The related gas-liquid parameters and microbial community diversity were measured, and the Tax4Fun analysis method was used to predict the methanogenic function of the methanogens. The results showed the following: i) Only the addition of Proteiniphilum acetatigenes and Bacteroides thetaiotaomicron produced significant colonization by functional microorganisms and strengthened the decomposition of organic matters in the fermentation system, especially protein, which improved the gas production efficiency. The average gas production by the PB (An experimental group only added Proteiniphilum acetatigenes and Bacteroides thetaiotaomicron) group was 1353.70 mL which was higher than that of the other groups by 19.27%–57.59%. ii) The dominant methanogens were Methanobacterium which mainly produced methane by using hydrogen and carbon dioxide as substrates according to the functional prediction. The results of the study reveal the biological strengthening mechanism of domestic waste landfill gas, which is conducive to improving the energy recycling efficiency of landfills.