Biochemical characterization of an endoxylanase from Pseudozyma brasiliensis sp. nov. strain GHG001 isolated from the intestinal tract of Chrysomelidae larvae associated to sugarcane roots

• Pseudozyma brasiliensis sp. nov. strain was isolated from the Chrysomelidae larvae.
• This basidiomycetous yeast produces a cellulase-free xylanase designated PbXynA.
• PbXynA has sigmoidal kinetic behavior with elevated speed conversion substrate–products.
• PbXynA is highly activated by bivalent cations such as Mg2+, Zn2+ and Ca2+.
• PnXynA has a high specific activity and produces xylooligosaccharides.

Endo-xylanases play a key role in the hydrolysis of xylan and recently they have attracted much attention due to their potential applications on the biofuel and paper industries. We isolated a Pseudozyma brasiliensis sp. nov. strain from the intestinal tract of Chrysomelidae larvae that parasitize sugarcane roots. This basidiomycetous yeast produces a xylanase designated PbXynA which was purified and characterized. The molecular weight of PbXynA is 24 kDa, it belongs to the GH11 family and its optimum pH and optimum temperature are 4.0 and 55 °C, respectively. PbXynA has as secondary structure predominantly β-sheets and sigmoidal kinetic behavior with elevated speed conversion from substrate-to-products (Vmax = 2792.0 μmol product/min/mg protein). It is highly activated by bivalent cations such as Ca2+, however in the presence of Cu2+ xylanase activity was inhibited. It has a high specific activity and produces xylooligosaccharides that have a variety of industrial applications, indicating PbXynA has a great biotechnological potential.