一株几丁质酶产生菌的筛选及产酶条件优化

Screening and Optimizing Conditions of Chitinase Production for Bradyrhizobiaceae blastobacter SYBC-H2

从浙江省台州市剑门港海区采集海底淤泥样本,以几丁质作为惟一营养因子,筛选出5株几丁质酶产生菌,对其中一株产酶活性较高的菌株从形态学、生理生化、脂肪酸组成及含量、G+C含量、醌型及分子生物学特征进行了鉴定(gene Bank:HM136777)。结果表明,该菌属于慢生根瘤菌科(Bradyrhizobiaceae),芽生杆菌属(Blastobacter)中的一种,命名为Bradyrhizobiaceae blastobacter SYBC-H2。P-B实验结果显示,几丁质、葡萄糖及玉米浆粉是该菌株产几丁质酶的关键营养因子,利用中心组合设计实验(Contral Composite Design)对该菌株的产酶培养基进行了成分优化,结果表明,当培养基主要成分几丁质、葡萄糖和玉米浆粉质量浓度分别为2.7、0.85、2.64 g/L时,几丁质酶活性最高,达到5.70 U/m L。

Five strains of bacteria producing chitinase were separated from Jianmen harbour seafloor mud in Taizhou of Zhejiang Province,China. One of strains with higher enzyme activity was further identified by morphology,physiology and biochemistry,composition and content of fatty acid,content of（G＋C） mol%,types of quinones,and molecular biological characteristics. The results showed that this strain belonged to the genus Blastobacter,named as Bradyrhizobiaceae blastobacter SYBC-H2. Moreover,the results of the Plackett-Burman Deisign experiments showed that chitin,glucose and corn steep powder were the key nutritional factors to produce chitinase. Composite Design Contral was applied to optimize the fermentative production of chitinase. As a result,the maximum chitinase activity was up to 5.70 U/mL when the culture medium was composed of 2.7 g/Lchitin,0.85 g/L glucose and 2.64 g/L corn steep powder.