Metagenomics and metagenome-assembled genomes analysis of sieng, an ethnic fermented soybean food of Cambodia

Abstract

Sieng is an ethnic fermented soybean food of Cambodia. No information on microbial community structures and their roles in health benefits of sieng is available till date. Hence, we aimed to profile the microbial community structures, to infer predictive functionalities and to recover the high-quality metagenome-assembled genomes (MAGs). Bacillus subtilis was the most abundant species in sieng, followed by Tetragenococcus halophilus, Enterococcus sp., Brevibacillus borstelensis, B. cereus, B. glycinifermentans, Halanaerobium praevalens, Mammaliicoccus sciuri, Staphylococcus gallinarum, Enterococcus faecium, B. cytotoxicus, Aneurinibacillus migulanus, B. thermoamylovorans, Paenibacillus dendritiformis and B. velezensis. Predictive functional profiles of sieng revealed several KEGG pathways and detection of CRISPR-Cas proteins. Six high-quality MAGs were recovered and identified as Bacillus subtilis, B. velezensis, B. glycinifermentans, B. borstelensis, B. thermoamylovorans and Ligilactobacillus acidipiscis. Genome annotation of recovered genomes showed biomarker genes for encoding several functional properties. Comparative analysis of previously reported microbiota in similar Asian sticky fermented soybean foods of other countries viz. Kinema of India, Nepal and Bhutan, pe poke of Myanmar and cheonggukjang of Korea with sieng was also studied. The PCoA plot showed a discrete variation between sieng and metagenomes of other similar fermented soybean foods, based on species level. However, sieng metagenome recorded the presence of halophilic bacterial species in higher abundance unlike other fermented soybean products. The present work is the first report on microbial community structure, and metagenome-assembled genomes of sieng.