一株产生淀粉分解酶犁头霉的分离鉴定及其酶学性质

Screening and identification of a novel rawstarch-digesting glucoamylase producing strain Absidia and its enzymatic property

摘要:

从保宁麸醋醋曲中定向筛选得到一株产生淀粉分解酶的菌株CQB43, 其酶活力为105.2 U/mL, RDA值达到27.9%。通过形态观察和分子生物学鉴定确定该菌株为伞枝犁头霉Absidia corymbifera。对该菌株分泌生淀粉酶酶学性质的研究结果表明, 该酶在pH为4.0?5.6的范围相对稳定, 最适pH是5.0; 在60 °C以下的范围内具有较好的热稳定性, 最适作用温度为40 °C。研究金属离子对其活力影响的结果表明, Co2+对该生淀粉糖化酶有激活作用, Fe3+和Ca2+对该酶有抑制作用。

Abstract:

A novel strain which could produce raw starch-digesting glucoamylase was isolated from Baoning bran vinegar Daqu and numbered as CQB43. Its raw starch-digesting glucoamylase activity was 105.2 U/mL and the RDA value was 27.9%. The species attribution of the strain was confirmed to be Absidia corymbifera by the characterization of morphological, and the similarity of the nucleotide sequence of the 26S rDNA gene and ITS region gene of the strain. Then the enzyme characters of the crude extracts produced by Absidia corymbifera CQB43 were studied. The optimum pH for the enzyme activity was 5.0, and it was very stable at the the pH range about 4.0-5.6. The optimum temperatures was 40 °C. Besides, the enzyme was very stable at the temperature of less than 60 °C, as its remnant activities was about 88% after 2 hours at 60 °C. According to the research on enzyme activity affected by metallic ion, it was activated by Co2+, whereas the activity was inhibited by Fe3+ and Ca2+.