高效产锰氧化酶鞘细菌的分离鉴定及酶学特性

从活性污泥中分离筛选锰氧化酶鞘细菌及研究酶学特性，利用尿素富集培养基、CGY平板及摇瓶复筛从水样中分离产锰氧化酶菌株，通过菌落形态观察、生理生化实验和16S rRNA基因序列对菌株进行鉴定，并对其发酵条件及所产锰氧化酶的酶学性质进行研究。结果表明，分离筛选到一株高产锰氧化酶的菌株FM-3，被鉴定为鞘细菌属纤发菌（Leptothrix）。该菌株的最适产酶条件为甘油添加量0.8%，蛋白胨添加量0.15 g/L，吐温-80添加量0.2%，30 ℃ 150 r/min振荡培养72 h，此时发酵液的锰氧化酶活性可达2 977.44 IU/mL。该菌株产锰氧化酶的最适温度和pH分别为40 ℃和7.0，添加一定量的Mg2+对锰氧化酶活性有增强作用，Ca2+、Cu2+对锰氧化酶影响不大，Pb2+、Zn2+、Ag+对锰氧化酶具有一定的抑制作用。

Isolation and identification of manganese-oxidase-producing Sheath bacteria and the enzymatic characterization

A strain of Sheath bacterium which produces manganese oxidase, was isolated and screened from activated sludge and the enzymatic characteristics were studied. The manganese-oxidase-producing strains were isolated from soil by the enrichment culture medium, CGY plate and shake flask culture. One strain was identified according to morphological features, physiological and biochemical analysis as well as 16S rRNA gene sequence analysis. And the fermentation conditions for producing manganese-oxidase and enzymatic characteristics were studied. The results shown that a bacterium FM-3 with high activity of manganese-oxidase was isolated. The strain was identified as Leptothrix FM-3. The optimal fermentation conditions for manganese-oxidase production were glycerol 0.8%, peptone 0.15 g/L, Tween-80 0.2%, at 30 ℃ 150 r/min oscillation for 72 h. Under these conditions, the activity of manganese oxidase fermentation liquid up to 2 977.44 IU/ml. The optimum temperature and pH value of manganese-oxidase were 40 ℃ and 7.0, respectively. Mg2+ could activate the manganese-oxidase, but Ca2+, Cu2+ had little impact. While Pb2+, Zn2+ and Ag+ had only modest inhibitory effect.