Effect of seeding materials on the composting process of model organic waste: Organic matter degradation and succession of microbial community

Abstract

Composting is a process of decomposing organic substances by microorganisms. Inoculation of microorganisms has been expected to accelerate the composting, but the effect is not clarified yet. This study aimed to investigate the effect of seeding materials on the degradation of organic matter and microbial community. Three types of seeding materials (one commercial seeding material and two commercial compost products) were compared in the lab-scale composting of model organic waste. The result showed that the degree of organic matter degradation tended to be similar at the end of composting process even irrespective seeding materials were used. However, the microbial community became different among three runs, indicating that the seeding materials influenced the succession of microbial communities. Next, the enzymatic genes of microorganisms were predicted through phylogenetic investigation of communities by reconstruction of unobserved states (PICRUSt). The abundance of most enzymatic genes became similar with the progress of composting in all conditions. This could infer that the functional potential of microorganisms is similar even the microbial communities were different. This finding clarified the effects of seeding materials during composting, from the aspect of the microbial community and the functional genes.