Production of xylanase from a novel engineered Pichia pastoris and application to enzymatic hydrolysis process for biorefinery

Abstract

In this study, the xylanase gene from Cellulomonas flavigena KCTC 9104 was cloned into pPICZ alpha B and expressed in Pichia pastoris X-33. An extracellular endo-1,4-beta-xylanase was produced by novel engineered P. pastoris (rXynCf) and purified by Ni-NTA affinity column. Characterization of rXynCf was performed and results are as follows: 38 kDa molecular weight, 55 degrees C optimum temperature and optimum pH of 6. Under the conditions, the K-m and V-max of rXynCf were 3.6 +/- 0.08 mg/mL and 4505 +/- 52 mu mol/min mg, respectively. rXynCf was applied in enzymatic hydrolysis process for sugars production from lignocellulosic biomass. Empty fruit bunch (EFB) was selected as a feedstock, and the total sugars conversion was found to be 3.8%, meanwhile the conversion by alkaline pretreatment improved approximately 16-fold (61.1%). In addition, rXynCf shows similar xylose conversion to commercial xylanase. Therefore, due to its properties, rXynCf has considerable potential in biorefinery applications.