Abstract:β-mannanase and xylanase are extensively used in food industry.Synergistic action between the two enzymes is obersved to effectively improve digestibility of the hemicelluloses of food material.In order to coexpress β-mannanase gene and xylanase gene in Pichia pastoris,pPIC9K-xynⅡ was linearized with Sal I and transformed into GS115/Anman5A by electroporation.GS115/Anman5A-xynⅡ with high production of β-mannanase and xylanase was screened by using G418.SDS-PAGE demonstrated two protein bands with apparent molecular weight of about 52 000 and 24 100.One GS115/Anman5A-xyn Ⅱ transformant producing the highest activities of two enzymes in shake flasks was selected and numbered as GSMX2.Subsequently the expression conditions for enzymes production by using GSMX2 were optimized,the optimum expression conditions listede as follows:initial pH 7.0,glycerol concentration 1.5%,methanol concentration 1.5%,induction for 120 h.Under these conditions,the activities of β-mannanase and xylanase were achieved at 37.1 U/mL and 193.6 U/mL,respectively.
