The biochemical mechanism of enhancing the conversion of chicken manure to biogenic methane using coal slime as additive

To improve the efficiency of methane production from chicken manure (CM) anaerobic digestion, the mechanism of coal slime (CS) as an additive on methane production characteristics were investigated. The results showed that adding an appropriate amount of CS quickened the start of the fermentation and effectively increased the methane yield. In addition, the pH changed in a stable manner in the liquid phase, and the concentrations of total ammonia nitrogen (TAN) and free ammonia nitrogen (FAN) were reduced. Moreover, organic matter was decomposed and volatile fatty acids (VFAs) were consumed effectively. The abundance of Bacteroides in the bacterial community and Methanosarcina in the archaea was increased. In addition, the reduction of CO2 was the main methanogenic pathway, and adding CS raised the abundance of genes for key enzymes in metabolic pathways during methane metabolism. The results provide a novel method for the efficient methane production from CM.

Automated summary

This study investigates the effects of coal slime as an additive on methane production characteristics in anaerobic digestion of chicken manure. The results show that adding an appropriate amount of coal slime can accelerate the fermentation process and enhance methane production. Moreover, it stabilizes the pH value in the liquid phase, reduces the concentrations of total ammonia nitrogen and free ammonia nitrogen, decomposes organic matter, and facilitates the consumption of volatile fatty acids. The bacterial community exhibits an increased abundance of Bacteroides, while Methanosarcina increases in the archaea. The reduction of CO2 is the main pathway for methanogenesis, and adding coal slime enhances the abundance of key enzyme genes in methane metabolism pathways.