Premium
β‐Glucan is a major growth substrate for human gut bacteria related to Coprococcus eutactus
Author(s) -
Alessi Anna M.,
Gray Victoria,
Farquharson Freda M.,
FloresLópez Adriana,
Shaw Sophie,
Stead David,
Wegmann Udo,
Shearman Claire,
Gasson Mike,
CollieDuguid Elaina S. R.,
Flint Harry J.,
Louis Petra
Publication year - 2020
Publication title -
environmental microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.954
H-Index - 188
eISSN - 1462-2920
pISSN - 1462-2912
DOI - 10.1111/1462-2920.14977
Subject(s) - biology , glycoside hydrolase , microbiology and biotechnology , cellobiose , laminarin , xyloglucan , glucan , gene , cellulase , biochemistry , polysaccharide , cellulose
Summary A clone encoding carboxymethyl cellulase activity was isolated during functional screening of a human gut metagenomic library using Lactococcus lactis MG1363 as heterologous host. The insert carried a glycoside hydrolase family 9 (GH9) catalytic domain with sequence similarity to a gene from Coprococcus eutactus ART55/1. Genome surveys indicated a limited distribution of GH9 domains among dominant human colonic anaerobes. Genomes of C. eutactus ‐related strains harboured two GH9‐encoding and four GH5‐encoding genes, but the strains did not appear to degrade cellulose. Instead, they grew well on β‐glucans and one of the strains also grew on galactomannan, galactan, glucomannan and starch. Coprococcus comes and Coprococcus catus strains did not harbour GH9 genes and were not able to grow on β‐glucans. Gene expression and proteomic analysis of C. eutactus ART55/1 grown on cellobiose, β‐glucan and lichenan revealed similar changes in expression in comparison to glucose. On β‐glucan and lichenan only, one of the four GH5 genes was strongly upregulated. Growth on glucomannan led to a transcriptional response of many genes, in particular a strong upregulation of glycoside hydrolases involved in mannan degradation. Thus, β‐glucans are a major growth substrate for species related to C. eutactus , with glucomannan and galactans alternative substrates for some strains.