Paenibacillus sp. GH10 and GH11 extracellular endoxylanases

GHIO, SILVINA; ONTAÑON, ORNELLA; PICCINNI, FLORENCIA; MARRERO DÍAZ DE VILLEGAS, RUBÉN; TALIA, PAOLA; RATNAPARKE, SUPRIYA

Conferencia; Cellulases and Other Carbohydrate-Active Enzymes Gordon Research Conference; 2017

The cost-efficient degradation of xylan to fermentable sugars is of particular interest in second generation bioethanol production, feed, food and pulp and paper industries. Multiple potentially secreted enzymes involved in polysaccharides deconstruction are encoded in the genome of Paenibacillus sp. A59, a xylanolytic soil bacterium, such as three endoxylanases (two GH10 and a GH11), seven GH43 β-xylosidases and two GH30 glucuronoxylanases. From these, only the three predicted endoxylanases were identified by mass spectrometry in xylan culture supernatant, confirming their active role. The two non-modular xylanases, a 32 KDa-GH10 and a 20 KDa-GH11, were recombinantly expressed and endoxylanase activity was confirmed (105.96 IU/mg and 85.04 IU/mg, respectively), releasing mainly xylobiose (X2) from xylan and pre-treated wheat straw. However, xylose (X1) was also released only by rGH10XynA, in consistence with other xylanases from GH10 family. By supplementing either enzyme with a GH43 beta-xylosidase we observed an increase in bioconversion rates to X1. However, addition of GH11 to GH10 did not result in additive or synergic activity, under any condition tested.