Dietary fibre degradation and fermentation by two xylanolytic bacteria Bacteroides xylanisolvens XB1A and Roseburia intestinalis XB6B4 from the human intestine

• Published in: Journal of applied microbiology Vol. 109; no. 2; pp. 451 - 460
• Main Authors: Mirande, C, Kadlecikova, E, Matulova, M, Capek, P, Bernalier-Donadille, A, Forano, E, Béra-Maillet, C
• Format: Journal Article
• Language: English
• Published: England 01.08.2010
• Subjects: Bacteroides - enzymology; Bacteroides - growth & development; Bacteroides - isolation & purification; Carbohydrate Metabolism; Colon - microbiology; Dietary Fiber - metabolism; Fermentation; Gram-Positive Bacteria - enzymology; Gram-Positive Bacteria - growth & development; Gram-Positive Bacteria - isolation & purification; Humans; Xylans - metabolism; Xylosidases - metabolism
• ISSN: 1365-2672
• DOI: 10.1111/j.1365-2672.2010.04671.x

To characterize fibre degradation, colonization and fermentation, and xylanase activity of two xylanolytic bacteria Bacteroides xylanisolvens XB1A(T) and Roseburia intestinalis XB6B4 from the human colon. The bacteria grew well on all the substrates chosen to represent dietary fibres: wheat and corn bran, pea, cabbage and leek fibres, and also on purified xylans. Roseburia intestinalis colonized the substrates more efficiently than Bact. xylanisolvens. For the two bacteria, 80-99% of the total xylanase activity was associated with the cells whatever the substrate and time of growth. Optimal specific activities of cells were obtained on oat spelt xylan; they were higher than those previously measured for xylanolytic bacteria from the human gut. Roseburia intestinalis produced high molecular mass xylanases (100-70 kDa), while Bact. xylanisolvens produced lower molecular mass enzymes, including a cell-associated xylanase of 37 kDa. The two bacteria display very high xylanolytic activity on the different substrates. Differences were observed on substrate attachment and enzyme systems, suggesting that the two species occupy different niches within the gut microbiota. This study characterizes xylan degradation by two major species of the human intestine.