Study On Fermentation Condition Of Xylanase From A.niger

Xylan is a component of plants that can be recycled in nature. Xylanase is the enzyme family that dehydrates xylan into xylose or oligoxylose. Xlyanase has extensive applications in the industries of feed, food, fabric and papermaking, and has become one of the hot spots of modern enzymology. Fermentation technics optimization and screening of the strain suitable for liquid fermentation were carried out on the basis of solid fermentation. The strain L suitable for liquid fermentation was selected by mutation of Co-60 with the A.niger 27,the xylanase high production strain as starting strain. The xylanase activity of the strain L on the selective medium of 5% wheat bran was 1966u/ml. Optimization of the medium was carried out on the level of flask, corncob, tryptone, Mg2+ and Hisdidane were selected for the production of xylanase. Effects of other factors, such as Tween-80 on the production of xylanase were also ascertained. After the orthonagol design, the optimal medium for the production of xylanase on the level of flask was established. The fermentation condition was also optimized and the xylanase activity reached 8226u/ml. The optimal temperature, pH, rotate speed and charge volume for xylanase production were 28-30℃, pH5.5, 220rpm and 50/500ml, respectively. The optimization of fermentation technics on the level of the jar was also carried out. The optimal medium for xylanase production was composed of 6%corncob, l%treptone and 0.3%urea. The optimal temperature, pH, vessel pressure, aeration rate and rotate speed were 30℃ in the first 14hr and 28℃ after 14hr, pH5.5 before sterilization, 0.06mpa~0.08mpa,l: 1.0-1.5 and 100~150rpm, respectively. The xylanase activity reached 7200u/ml after optimization.