Bacterial community succession in dairy manure composting with a static composting technique

This study applied high-throughput sequencing technology and PICRUSt (phylogenetic investigation of communities by reconstruction of unobserved state) to examine the microbial population dynamics during the composting of dairy manure and rice straw in a static (without turning) composting system. The results showed that the composition of the bacterial community varied significantly during the composting process. The dominant phyla included Firmicutes, Proteobacteria, Bacteroidetes, Actinobacteria, and Chloroflexi. Biodiversity indices showed that bacterial community diversity had the peak value during the mesophilic phase. Redundancy analysis indicated that nitrogen was the most important factor in the distribution of genera during the composting process. Finally, the Pearson correlation results suggested that Thermomonospora and Thermopolyspora could be the biomarkers of the composting maturation phase. The metabolic characteristics of the bacterial communities were predicted by PICRUSt. The result showed that metabolism of amino acids, lipids, and most of the carbohydrates increased during the whole composting treatment. However, methane metabolism, carbon fixation pathways in prokaryotes, and nucleotide metabolism decreased after the thermophilic phase. The present study provides a better understanding for bacterial community composition and function succession in dairy manure composting.