ABSTRACT
Streptomyces sp. A048 was cultured in a complete medium to the last stage of log phase,the hyphae were washed and collected by centrifugation. Then the hyphae were inoculated in liquid medium for chitinase production using two-step fermentation. Activity of chitinase produced by two-step fermentation was 1.1 times higher than that from one-step fermentation,and ferment cycle was for 54 hours,which was 66 hours shorter than that of one-step fermentation. The hyphae and the powder of chitin were co-immobilizated and cultured in liquid medium for 36 hours,activity of chitinase was 1.8 times higher than that from one-step fermentation,and ferment cycle was 54h shorter than that of one-step fermentation. By adding 0.4% cellulose to two-step fermentation,activity of chitinase was 18.52 U/mL that was 4 times higher than that from the control and 10 times higher than that from one-step fermentation. Two step fermentation with chitin and cellulose may be the optimal fermentation process to produce Chitinase from Streptomyces sp. A048.
ABSTRACT
A.niger M1, the initial strain, was treated by UV and a mutant with 30% higher xylanase activity was obtained. Zymogram for detecting xylanase showed there are three different xylanases in the mutant mature culture, while two xylanases in initial strain. After orthogonal experiment, the optimum fermentation conditions of the mutant were obtained as follows: concentration of the major carbon resource 4 %, ratio between bran and corncob 5:5, concentration of glucose 0.1%, concentration of ammonium oxalate as supplemental nitrogen resource 2.0%, the initial pH of liquid medium 5.0, 100mL/250mL flask.