Isolation of novel microorganisms from the human gut

Abstract

During the studies of two projects of the Institute for Fermentation, Osaka (IFO) and Japan Agency for Medical Research and Development (AMED), we isolated a large number of bacteria from the human feces and proposed 13 novel species until now. Among the novel species, there are butyrate-producing and succinate-utilizing bacteria, such as Lawsonibacter asaccharolyticus and Dialister hominis. In our studies, only strains that formed colonies on agar plate media were isolated. Recently, new isolation methods that do not rely on agar media have been developed. To understand microbe-microbe interactions, we investigated the growth behavior of co-cultured Bacteroides thetaiotaomicron and succinate-utilizing bacteria, such as Phascolarctobacterium faecium and D. hominis. Co-existence with succinate-producing bacteria, such as Bacteroides, is essential for succinate-utilizing bacteria to inhabit the human gut and produce propionate. In this review, new insights into the isolation of novel microorganisms from the human gut are discussed.