Enzymatic activities triggered by the succession of microbiota steered fiber degradation and humification during co-composting of chicken manure and rice husk

Abstract

The carbon to nitrogen ratio (C/N) is well known for its importance in the composting process, however the fiber degradation and humification associated with enzymatic activity and microbial variation derived from different C/N ratios are poorly studied. Here, we designed two treatments of chicken manure with 15% (initial C/N ratio 9.61) and 50% (initial C/N ratio 17.3) rice husk to adjust the moisture of mixtures for turning feasibly by towable fertilizer turner in industrial level. Compared to the C/N ratio 9.61, the suitable C/N ratio of 17.3 significantly enhanced the composting efficiency and the final germination index (23.7%). Moreover, the suitable C/N ratio increased the relative abundance of Bacilli, which played an important role during the mesophilic and thermophilic phases. Bacilli abundance was related to cellulose and β-glycosidase activities, thus improved fiber degradation and humification. This study not only seeks a swift method in industrial level to process chicken manure but also provides insight into the enzymatic activity of microbial community related to high-efficient composting.