Engineering the Xylan Utilization System in Bacillus subtilis for Production of Acidic Xylooligosaccharides

摘要: ABSTRACT Xylans are the predominant polysaccharides in hemicelluloses and an important potential source of biofuels chemicals. The ability Bacillus subtilis subsp. strain 168 to utilize xylans has been ascribed secreted glycoside hydrolase family 11 (GH11) GH30 endoxylanases, encoded by xynA xynC genes, respectively. Both these enzymes have defined with respect structure function. In this study, effects deletion individually combination, were evaluated for xylan utilization formation acidic xylooligosaccharides. Parent depolymerizes methylglucuronoxylans (MeGXn), releasing xylobiose xylotriose utilized growth accumulating aldouronate methylglucuronoxylotriose (MeGX3) some methylglucuronoxylotetraose (MeGX4). combined GH11 activities process products generated their respective actions on MeGXn release a maximal amount neutral xylooligosaccharides assimilation growth, at same time forming MeGX3 which internal xylose is substituted methylglucuronate (MeG). Deletion results accumulation β-1,4-xylooligosaccharides degrees polymerization ranging from 4 18 average degree substitution 1 7.2, each single MeG linked α-1,2 penultimate reducing terminus. gene aldouronates comprised or more residues may be nonreducing xylose. These B. lines used production applications human veterinary medicine.