Enumeration and isolation of cellulolytic and hemicellulolytic bacteria from human feces

Abstract

The fibrolytic microbiota of the human large intestine was examined to determine the numbers and types of cellulolytic and hemicellulolytic bacteria present. Fecal samples from each of five individuals contained bacteria capable of degrading the hydrated cellulose in spinach and in wheat straw pretreated with alkaline hydrogen peroxide (AHP-WS), whereas degradation of the relatively crystalline cellulose in Whatman no. 1 filter paper (PMC) was detected for only one of the five samples. The mean concentration of cellulolytic bacteria, estimated with AHP-WS as a substrate, was 1.2 X 10(8)/ml of feces. Pure cultures of bacteria isolated on AHP-WS were able to degrade PMC, indicating that interactions with other microbes were primarily responsible for previous low success rates in detecting fecal cellulolytic bacteria with PMC as a substrate. The cellulolytic bacteria included Ruminococcus spp., Clostridium sp., and two unidentified strains. The mean concentration of hemicellulolytic bacteria, estimated with larchwood xylan as a substrate, was 1.8 X 10(10)/ml of feces. The hemicellulose-degrading bacteria included Butyrivibrio sp., Clostridium sp., Bacteroides sp., and two unidentified strains, as well as four of the five cellulolytic strains. This work demonstrates that many humans harbor intestinal cellulolytic bacteria and that a hydrated cellulose source such as AHP-WS is necessary for their consistent detection and isolation.

The cellulolytic microflora of the human colon: evidence of microcrystalline cellulose-degrading bacteria in methane-excreting subjects

“…Only 40% of the volunteers included in our study were shown to harbour ¢lter paper microcrystalline cellulosedegrading micro-organisms in the gut. This result is consistent with previous observations from Be ¤tian et al [4], Montgomery [5] and Wedekind et al [6] who reported that only a restricted number of individuals (one or two subjects of the six studied) harboured such cellulolytic microorganisms. These authors explained the failure to detect Cellulolytic isolates were incubated for 10 days at 37 ‡C with 100 mg of Whatman No.…”

Characterization of the xylan-degrading microbial community from human faeces

“…Only one Gram-positive rod, closely related to members of cluster IV of Clostridiaceae, was isolated from one faecal specimen. Similarly, Wedekind et al (1988) previously reported the isolation of a larchwood xylandegrading strain which, based on its morphological and phenotypic characteristics, was assigned to the genus Clostridium. The xylanase activity of Clostridium isolate was difficult to evaluate despite its effective growth in xylan medium as shown for B. dorei-related strains.…”

“…Plant polysaccharides breakdown represents the first step of this fermentative process that is ensured by fibrolytic bacteria (comprising cellulolytic and hemicellulolytic bacteria) through production of different hydrolytic enzymes. Despite their prominent roles, these fibre-degrading populations of the human gut have not been extensively studied (Bétian et al, 1977;Montgomery, 1988;Wedekind et al, 1988;Robert & Bernalier-Donadille, 2003). In this context, we recently showed that the structure and activity of the cellulose-degrading population greatly vary according to the methane-status of the subject considered (Robert & Bernalier-Donadille, 2003).…”

Isolation of a novel strain of Butyrivibrio fibrisolvens that isomerizes linoleic acid to conjugated linoleic acid without hydrogenation, and its utilization as a probiotic for animals

“…Butyrivibrio fibrisolvens also resides in the intestines of humans (Wedekind et al 1988), dogs and cats (Asanuma et al 2001). We previously demonstrated that CLA is produced in small amounts by mixed bacteria in dog and cat faeces (Fukuda et al 2002).…”