Xylan solubilization and use as carbon source/inductor for microbial xylanase production / Solubilização de Xylan e utilização como fonte/indutor de carbono para a produção de xilanase microbiana

Abstract

Xylanases are enzymes that hydrolyze the main chain of xylan, producing xylooligosaccharides and xylose. These enzymes are of great importance for the pharmaceutical industries and also for the production of biofuels. For the production of microbial xylanases, xylan substrate is used, which can be obtained from different biomass such as sugarcane residue. However, the problem when using commercial xylanases for xylanase induction is its high cost. In this context, this study sought to use a methodology for extracting xylan from sugarcane in alkaline medium quickly and inexpensively, and also the application of this xylan as substrate for xylanase production, using for both fungi Aspergillus nidulans, Aspergillus tubingensis and Aspergillus versicolor. The cultures in the presence of 1% xylan for these microorganisms were compared with cultures containing 1% wheat bran, an important substrate for xylanase production. The results indicate that xylan extracted by this methodology, besides presenting some amount of lignin, contributed to a higher production of xylanases for A. nidulans, and in A. tubingensis and A. versicolor the production was close to the when wheat bran was used as an inducer.