一株产淀粉酶的克雷伯氏菌株的分离鉴定及其产酶条件优化

从酒酿、酒曲样品中,采用透明圈法对淀粉酶产生菌株进行初筛,并通过测定酶活对其进行复筛.对所筛选出的产淀粉酶能力较高的菌株进行形态特征观察、生理生化鉴定及16S rDNA序列测定.经鉴定是克雷伯氏菌属,将其命名为Klebsiella sp.ZSY-I.通过正交实验对该菌株产酶的影响因素进行优化,结果表明：对菌株产酶影响较大的因素依次为KNO3、温度、淀粉和pH.该菌株在淀粉含量为2.5%,KNO3含量为1.25%的培养基上,30℃和初始pH为7.5,培养24 h后,酶活力达到最高为14.66 U/mL.

Isolation and Identification of a Klebsieila sp. Strain Produced Amylase and Optimization of Conditions for Enzyme Production

The aim of our Study is to isolate a strain with amylase high producing capability and to optimize the fermentation conditions to increase enzyme production. Samples from sweet fermentedrice and mold culture were used to screen amylase producing strains. The target strain was selected by comparing the haloes of colonies from starch plate and measuring enzyme activity. The strain was identified according to the morphology characterization, physiological and biochemical properties and 16S rDNA sequence analysis. An amylase high producing strain was screened and identified as Klebsiella sp. ZSY- I. The culture conditions for enzyme production were optimized through orthogonal test. The factors affecting the enzyme production was shown as KNO3 （%） 〉 Temperature （℃） 〉 Starch（%） 〉 pH. The maximum amylase activity produced by ZSY - I was 14. 66 U/mL on the culture medium containing starch 2.5 %, KNO3 1.25 % at 30℃ and initial pH 7.5 for 24 h.