Study of the xylanolytic potential of four recombinant xylanases from Cellulomonas sp. B6

ONTAÑON, ORNELLA; PICCINNI, FLORENCIA; GHIO, SILVINA; GARRIDO, MERCEDES M; CAMPOS, ELEONORA

San Martín

Simposio; 3rd Argentinian Symposium on Glycobiology; 2019

The enzymatic degradation of structural polysaccharides is ofinterest for the sustainable processing of biomass into valueadded products. Cellulomonas sp. B6, a native (hemi)cellulolyticstrain is a promising source of polysaccharide-degradingenzymes since it secretes multiple xylanases by growing onlignocellulose.We have characterized three GH10 (Xyl1Cel10, Xyl2Cel10, andXyl3Cel10) and one GH11 (Xyl4Cel11) xylanases encoded in thegenome of Cellulomonas sp. B6. The optimal activity conditionsof the recombinant enzymes were defined by factorial design andvalidated by the study of the independent variables. In general,the xylanases showed optimal activity at neutral pH and 30-45°C,but Xyl1Cel10 performed better at 55°C and was the mostthermally stable. None of the enzymes hydrolyzed cellulosicsubstrates, demonstrating high specificity for xylan. The activityranged from 80 to 350 U/mg for GH10 xylanases and around 60U/mg for Xyl4Cel11 on the preferred substrates beechwoodglucuronoxylan and wheat arabinoxylan, but decreasedsignificantly on xylan with higher content of glucuronic acid orarabinoxylan containing pectin residues. The hydrolysis productsof Xyl4Cel11 were xylooligosaccharides (XOS) of variable length(DP 2-6) while GH10 xylanases released shorter XOS andxylose. Therefore, these enzymes may be suitable in differentindustrial processes for biomass bioconversion such as obtainingprebiotic XOS