海洋菌W11产中温淀粉酶的酶学特性

本研究从威海文登海域筛选获得一株产淀粉酶海洋菌W11,初步鉴定为弧菌,并探讨pH、温度、无机离子对淀粉酶活性和稳定性的影响及该酶底物浓度效应和Km值。结果表明:在pH7.5左右酶活性最高,pH在4.0～7.5范围内体现较强的稳定性。最适酶解温度为55℃,酶液在60℃以下有较好的热稳定性;Ba2+、Mn2+对淀粉酶有激活作用,而Cu2+、Mg2+、Zn2+则抑制淀粉酶活性,表观Km值为0.973mg/mL。海洋菌W11所产的中温淀粉酶保存温度范围较广、适应pH作用的范围广及稳定性较强,将有着广泛的应用潜力。

Enzymatic Characteristics of Mesophilic Amylase from a Marine Bacterium Strain W11

In this study, we have screened and isolated a marine bacterium strain W11 which produce mesophilic amylase from the sea area of Wendeng, Weihai, and it was initially identified as Vibrionaceae. Then we investigat-ed the effect of pH, temperature and inorganicion on amylase activity and stability of the mesophilic amylase, and we also studied the substrate concentration effect of this amylase and measured its Km value. The results showed that the optimum pH of the amylase was 7.5, and the amylase was stable when pH from 4.0 to 7.5. The optimum temperature of the amylase was 55℃ and it could work continuously under temperature of 60℃. Ba~(2+), Mn~(2+) had activation but Cu~(2+), Mg~(2+), Zn~(2+) had inhibition on activity of the amylase, and the Km value of the amylase was mea-z sured as 0.973 mg/mL. The mesophilic amylase of strain W11 showed the widely temperature range of conserva-tion, widely range of accommodation and better stability of pH which should be make it has the far-reaching po-tential of application.