中文摘要：

从运城盐湖分离获得一株可产淀粉酶的嗜盐细菌菌株X50,对其进行分类鉴定及酶学特性分析。采用底物平板法进行菌株X50产胞外淀粉酶活性检测。通过16S rRNA基因序列分析对其进行分类鉴定。研究不同因素对菌株X50所产淀粉酶活性的影响。16S rRNA基因序列分析结果表明,该菌为Thalassobacillus属成员,命名为Thalassobacillus sp.X50。对其所产淀粉酶酶特性进行了初步研究,结果发现该酶最适pH值为6.0,在较宽pH范围内（4.0～12.0）可保持高活力,具有较强的耐酸碱能力。无盐条件下,酶活性最强,且该酶具有良好的耐热性,高温处理后仍可保持较高活性。除Mg2＋对酶的抑制作用较为显著外,其他金属离子基本无影响。PMSF可明显抑制该酶活性,而DEPC和EDTA作用不明显,表明该酶活性中心不含金属离子,可能为丝氨酸蛋白酶。本文的研究结果将为促进运城盐湖极端微生物资源的开发利用提供参考。

英文摘要：

A halophilic bacterium strain X50 that could produce amylase was isolated from Yuncheng salt lake,and carried out its classification and characterizations,and enzymological properties analysis. The activity of extracellular amylase produced by strain X50 was determined adopting substrate plate method. And studied the effects of different factors on the amylase activity produced by the strain X50. The results of 16 S rRNA gene sequence analysis showed that the strain was Thalassobacillus,and named it as Thalassobacillus sp. X50. The results of initial study on the enzymology of the amylase showed the optimal pH of the amylase was 6. 0,and maintained its high activity at fairly wide range of pH at 4. 0 ～ 12. 0,and possessing fairly strong resistance capacity against acid-base. Under salt-free condition,the amylase activity was the strongest,furthermore,it has fine property of heat resistance,even after high temperature treatment. Except for Mg2 ＋that significantly inhibited the amylase,basically no effects of other metal ions on it. PMSF could significantly inhibit its activity,however,the effect of DEPC and EDTA on the amylase activity was not significant,indicated that the center of the enzyme activity contained no metal ion,probably was serine protease.The results of this study provide theoretical foundation and will promote the development and utilization of the extreme microbial resources in Yuncheng salt lake.