Prevotella copri is a bacterium that can be found in the human gastrointestinal tract (GIT). The role of P. copri in the GIT is unclear, and elevated numbers of the microbe have been reported both in dietary fiber-induced improvement in glucose metabolism but also in conjunction with certain inflammatory conditions. These findings raised our interest in investigating the possibility of P. copri to grow on xylan, and identify the enzyme systems playing a role in digestion of xylan-based dietary fibers. Two xylan degrading polysaccharide utilizing loci (PUL10 and 15) were found in the genome, with three and eight glycoside hydrolase (GH) -encoding genes, respectively. Three of them were successfully produced in Escherichia coli: One extracellular enzyme from GH43 (subfamily 12, in PUL10, 60 kDa) and two enzymes from PUL15, one extracellular GH10 (41 kDa), and one intracellular GH43 (subfamily 137 kDa). Based on our results, we propose that in PUL15, GH10 (1) is an extracellular endo-1,4-β-xylanase, that hydrolazes mainly glucuronosylated xylan polymers to xylooligosaccharides (XOS); while, GH43_1 in the same PUL, is an intracellular β-xylosidase, catalyzing complete hydrolysis of the XOS to xylose. In PUL10, the characterized GH43_12 is an arabinofuranosidase, with a role in degradation of arabinoxylan, catalyzing removal of arabinose-residues on xylan.

The behavior of three isolates retrieved from different cellulolytic consortia, Bacillus sp. AR03, Paenibacillus sp. AR247 and Achromobacter sp. AR476-2, were examined individually and as co-cultures in order to evaluate their ability to produce extracellular cellulases and xylanases. Utilizing a peptone-based medium supplemented with carboxymethyl cellulose (CMC), an increase estimation of 1.30 and 1.50 times was obtained by the co-culture containing the strains AR03 and AR247, with respect to enzyme titles registered by their individual cultivation. On the contrary, the extracellular enzymatic production decreased during the co-cultivation of strain AR03 with the non-cellulolytic Achromobacter sp. AR476-2. The synergistic behavior observed through the combined cultivation of the strains AR03 and AR247 might be a consequence of the consumption by Paenibacillus sp. AR247 of the products of the CMC hydrolysis (i.e., cellobiose and/or cello-oligosaccharides), which were mostly generated by the cellulase producer Bacillus sp. AR03. The effect observed could be driven by the requirement to fulfill the nutritional supply from both strains on the substrate evaluated. These results would contribute to a better description of the degradation of the cellulose fraction of the plant cell walls in nature, expected to an efficient utilization of renewable sources.