球孢白僵菌Bb174固态发酵产几丁质酶产酶及酶学特征研究

对球孢白僵菌(Beauveria bassiana)Bb174产几丁质酶进行了固态发酵条件及酶学特征的研究．结果表明，以4：1麸皮：蚕蛹粉、蛋白胨1g·L^-1作为产酶最适培养基，在7．5g培养基中接种3ml液态种子，自然pH下28℃培养2d，酶活可达最高，为126U·g^-1(干培养基)．粗酶液的最适反应温度为40℃，最适反应pH5．0，在30-70℃保温1h，得半失活温度48℃．在30--40℃、pH4～6范围内，酶的性质最稳定．根据Lineweaver-Burk作图法，得到该酶的动力学参数Km为0．52mg·ml^-1，Vm为0．7△E680·h^-1．

Production and properties of chitinase from Beauveria bassiana Bb174 in solid state fermentation

This paper studied the chitinase production of Beauveria bassiana Bb174 under solid state fermentation condition. The optimal medium consisted of wheat bran and silkworm chrysalis at the ratio of 4:1, supplemented with 1 g peptone L(-1) as nitrogen source and some other mineral nutrients. The enzyme activity reached 126 units per gram dry medium after cultured for 2 days at 28 degrees C and natural pH by inoculated 3 ml spore suspension into this medium. The optimal temperature and pH for chintinase production were 40 degrees C and 5.0, respectively. The temperature to lose 50% activity of the enzyme was 48 degrees C after incubated at 30-70 degrees C for 1 h. The enzyme was stable at 30-40 degrees C and pH 4-6, and the Km and Vmax values were 0.52 mg x ml(-1) and 0.7 deltaE680 x h(-1), respectively.