低温葡聚糖内切酶产生菌的筛选、鉴定及酶学性质

Screening and identification of a cold-active endoglucanase-producing strain and its endoglucanase characterization

摘要:

自黄海长海县附近海泥中分离得到一株产低温葡聚糖内切酶的菌株SWD-28, 经形态学及ITS 序列鉴定为Penicillium cordubense。对该菌株产的粗酶液进行硫酸铵盐析和Sephadex G100柱层析, 比活力达到26.4 U/mg, 提高20.6 倍, 回收率13.1%。得到一个电泳纯的低温葡聚糖内切酶, 分子量为33.1 kD。经圆二色对其结构进行检测, 发现其α-螺旋占49.9%, β-折叠占0.0%, 转角占24.3%, 随机卷曲占25.8%, 呈典型α 螺旋。对其酶学性质进行初步研究, 结果表明其最适pH为5.0, 最适反应温度为35 °C, 在5 °C 酶活力仍能保持60%。

Abstract:

A strain SWD-28 producing cold-active endoglucanase was isolated from samples of Changhai county in Yellow Sea. It was identified as Penicillium cordubense based on the morphological and ITS sequence. An endoglucanase was isolated and purified from it. The specific activity of endoglucanase was 26.4 U/mg increased 20.6 fold and coefficient of recovery was 13.1%, the molecular mass was 33.1 kD. Analysis by circular dichroism (CD) spectrum of purified endoglucanase protein revealed that it displayed typical α-helix structure and α-helix 49.9%, β-sheet 0.0%, turn 24.3% and random coil 25.8%. Enzymatic properties showed that the optimum pH value is 5.0 and the optimum reaction temperature is 35 °C, at 5 °C the relative enzyme activity still reach to 60%.