Fungal β-glucan-facilitated cross-feeding activities between Bacteroides and Bifidobacterium species

Abstract

The human gut microbiota (HGM) is comprised of a very complex network of microorganisms, which interact with the host thereby impacting on host health and well-being. β-glucan has been established as a dietary polysaccharide supporting growth of particular gut-associated bacteria, including members of the genera Bacteroides and Bifidobacterium, the latter considered to represent beneficial or probiotic bacteria. However, the exact mechanism underpinning β-glucan metabolism by gut commensals is not fully understood. We show that mycoprotein represents an excellent source for β-glucan, which is consumed by certain Bacteroides species as primary degraders, such as Bacteroides cellulosilyticus WH2. The latter bacterium employs two extracellular, endo-acting enzymes, belonging to glycoside hydrolase families 30 and 157, to degrade mycoprotein-derived β-glucan, thereby releasing oligosaccharides into the growth medium. These released oligosaccharides can in turn be utilized by other gut microbes, such as Bifidobacterium and Lactiplantibacillus, which thus act as secondary degraders. We used a cross-feeding approach to track how both species are able to grow in co-culture.

In Vitro and In Vivo Antihyperglycemic Effects of New Metabiotics from Boletus edulis

“…While the main effects of medicinal mushrooms are attributed to the beta-glucan content, polyphenols can enhance the antioxidant effect and restore dysregulated metabolic processes [18,[29][30][31]. All the extracts tested herein contain rutin in significant amounts, which can partly explain their antidiabetic and microbiota-modulating properties.…”

Positive modulation of a new reconstructed human gut microbiota by Maitake extract helpfully boosts the intestinal environment in vitro

“…However, the precise mechanism of β-glucan metabolism by every commensal gut bacterium is not elucidated yet. Only the recent work of Fernandez-Julia et al [ 54 ] presents a cross-feeding approach employing co-cultures of Bacteroides cellulosilyticus , Bifidobacterium , and Lactiplantibacillus in the presence of β-glucans. In this case, the authors suppose that the Bacteroides strain has two extracellular enzymes that can degrade the complex polysaccharides, and then release oligosaccharides in the medium.…”