Succession of bacterial communities during composting process as detected by 16S rRNA clone libraries analysis

Abstract Bacteria act as the dominant degraders during the composting process, although fungi also play important roles. In the present study, a 112-day aerobic composting by dairy manure and rice chaff was conducted. Four 16S rRNA gene clone libraries were constructed from samples taken at days 0, 12, 42 and 112, and a total of 779 randomly selected clones were sequenced. The coverage values calculated with the DOTUR program based on a 98% sequence similarity criterion ranged between 0.75 (day 112) and 0.94 (day 42). The results showed that the bacterial communities varied significantly during the composting process. Firmicutes and Proteobacteria were the two most abundant phyla at all stages. Bacteroidetes and Chloroflexi were ubiquitous. The phylum Actinobacteria was dominant only at the thermophilic stage (day 42). A slight increase in bacterial diversity at the phylum and genus levels was observed as the composting process progressed, but different results were obtained at the species level. Moreover, sequences belonging to the candidate phylum BCR1 were determined in this experiment. This study may provide a better understanding of the bacterial community composition and succession during the composting process.