Effects of bamboo powder on nitrogen dynamics and microbial succession in kitchen food waste composting

Abstract

Nitrogen is an important element in the composting process and one of the main components of microbial cells. In this study, bamboo powder and perishable organic waste were used as raw materials to construct a composting system with a 10 % mass ratio of microbial agents. The composition, structure and functional genes of bacteria during composting were analysed by high-throughput sequencing technology. The thermal period of the compost was extended by 7 days after the addition of bamboo powder, and the abundance of the bacterial community increased. Firmicutes, Proteobacteria, Actinobacteria and Bacteroides were the main dominant compost phyla, and their presence promoted the significant enrichment of Bacillus palustris and cellulobacteria. The addition of bamboo powder significantly increased the concentrations of ammonia nitrogen (NH₄⁺-N), nitrate nitrogen (NO₃^--N), and other nutrients. After treatment, the seed germination index was 2.8 times greater than that of the control group, and the EC decreased to 1.5 mS/cm, which was conducive to conversion into organic fertilizer. The results of the multifactor analysis showed that after the addition of bamboo powder, Corynebacterium, Ochrobactrum and Streptomyces are the key bacterial genera that can affect nitrogen conversion during composting. The metabolic function of bacteria was predicted based on the KEGG (Kyoto Encyclopedia of Genes and Genomes) database, which includes information on various metabolic pathways, such as amino acid transformation and genetic information processing. The addition of bamboo powder increased the maturity and nutrient content of the compost products and changed the dynamics of the compost bacterial community.