MEDIUM ENGINEERING FOR PRODUCTION OF CELLULASE FREE THERMOSTABLE XYLANASE FROM Bacillus sp. XPB-7

Xylanase production from Bacillus sp. XPB-7 was observed in the medium containing xylan, meat extract, glucose and further modified by optimization of the concentrations of individual components. Maltose at 100 mM concentration proved to be the most suitable carbon source for production of xylanase activity from Bacillus sp. XPB-7. For nitrogen source; inorganic and organic nitrogen supplements were tested and maximum production was observed in 0.5% tryptone. Temperature 30°C, pH 7.5, substrate concentration 1% and inoculum size 8% was optimum for the growth and xylanase production respectively. Optimum time observed for growth and enzyme production was 24 hours. 55 mM potassium phosphate buffer (pH 8.5) at 55°C and 10 minutes incubation temperature gave maximum xylanase activity. For thermo stability, the enzyme was fairly stable at 40°C and 60°C. The various metal ions (1mM CuSO4.5H2O, ZnSO4.7H2O, HgCl2 etc.,) showed drastic decrease in xylanase activity.