[Construction of gut microbial culture banks: advances, methods and perspectives]

Recently, the gut microbiota-based live biotherapeutics (LBPs) development, the interaction between gut microbial species and the host, and the mining of new antimicrobial peptides, enzymes and metabolic pathway have received increasing attention. Culturing gut microbial species is therefore of great importance. This review systemically compared the construction advances of gut microbial culture banks and also analyzed the differences of methods used by research groups to give insight into the construction and enrichment of gut microbial resources. Presently, the gut microbial culture banks have included more than 1 000 bacterial species, belonging to 12 phyla, 22 classes, 39 orders, 96 families, and 358 genera. Among these, Firmicutes, Proteobacteria, Bacteroidota, and Actinomycetota exhibited the greatest diversities at the species level. The sequencing data showed that there are more than 2 000 species inhibited in the human gut. Therefore, the cultured gut microbial species are far from saturation. In terms of the construction method, the stool samples were pre-treated with ethanol or directly spread and cultured in the non-selective nutritional rich medium (represented by Gifu anaerobic medium) to obtain single colony. Then single colony was further purified. Generally, a simplified isolation and culture method is sufficient to obtain the most common and important intestinal bacterial species, such as Bifidobacteria-Lactobacillus, Akkermansia muciniphila, Faecalibacterium prausnitzii, Prevotella and S24-7 family strains. Finally, microbial resources with great diversities at the strain level are required for further functional research and product development. Samples covering hosts with distinct physiological status, diets or regions are necessary.