Metagenomics and metatranscriptomics analysis of the microbial community structure and metabolic potential of fermented soybean in Yunnan Province

Traditional fermented soybean contains a variety of microflora. To obtain a comprehensive and accurate understanding of the microbial community structure and metabolic potential of fermented soybean, comparative metagenomics and metatranscriptomics were performed on a sample of fermented soybean collected from the Prefecture of Dehong in Yunnan Province. Metagenomics DNA and metatranscriptomics RNA were sequenced using Illumina HiseqTM2500. The assignment of metagenomics sequences to SEED (http://www.theseed.org/wiki/Home_of_the_SEED) categories of the Metagenome Rapid Annotation using Subsystem Technology (MG-RAST) server revealed that Providencia stuartii was the most abundant species and that the genes of carbohydrates (2296, 13.30%), protein metabolism (1530, 8.86%), and amino acids and amino acid derivatives (1423, 8.24%) were dominant. The expression levels of the genes belonging to the amino acid transport and metabolism processes were the highest according to the reads per length of transcript in kilo-bases per million mapped reads (RPKM) values, followed by energy production and conversion and carbohydrate transport and metabolism.