Optimization of xylanase production by Penicillium citrinum xym2 and application in saccharification of agro-residues

The production of thermostable xylanase by a newly isolated Penicillium citrinum xym2 was optimized by one factor at a time (OFAT) and response surface methodology (RSM) approaches. Optimization of xylanase production by OFAT approach indicated medium pH 4.0, wheat bran 1% (w/v), maltose 1.25% (w/v), di-ammonium hydrogen phosphate 0.09% (w/v), cultivation temperature 30 °C, and incubation time 72 h as optimal conditions for xylanase production of 1853 IU/ml. Three effective variables, wheat bran concentration, medium pH and cultivation temperature were optimized by central composite rotatable design (CCRD) based RSM. The interactions between these variables contributed to significant increased xylanase production. The RSM optimized wheat bran level 1.5% (w/v), pH (3.5) and temperature (30 °C) enhanced xylanase production to 2834 IU/ml. The production value or enzyme production was closer to the model diagnosed value of 2845 IU/ml and was about 4 fold higher than in unoptimized basal medium. The enzyme showed potential in saccharification of second generation feed stocks into sugars.