Screening of Tow Xylanase-producing Fungus Strains and Study on Enzymological Properties of Produced Xylanases

Two strains of fungi (C_4 and G_1) producing high activity xylanase were isolated by soil dilution coating method and through primary and repeated screening.Furthermore,the optimum carbon source for their growth and enzymological proper- ties of xylanases produced by them were studied.The results showed that the best carbon source for strain C_4 producing xylanase is the mixture of corncob and bran.The xylanse activity produced by strain G_4 reaches the peak after cultivation for 24h,6582. 29 U/ml.The optimum reaction temperature of the xylanse is 40℃and it is relatively stable below 50℃.Its optimum reaction pH is 5.0 and it shows good pH stability;The best carbon source for strain G_1 producing xylanase is corncob.The xylanase activity produced by strain G_1 reaches the peak after 96 hours of cultivation,6301.04 U/ml.The optimum reaction temperature of xylanase produced by strain G_1 is 40℃and it is stable below 40℃.The optimum reaction pH is 5.0,but its stability is less than that of xylanase produced by strain G_4.