极端嗜盐菌筛选鉴定及诱导碳酸盐矿化研究

Study on Isolation and Identification of an Extreme Halophilic Bacterium and Its Induction of Carbonates Mineralization

摘要: 以胶南尹家山盐场采集的盐泥样品为基础，用标准方法筛选得到7株到耐25%盐度的菌，选取生长较好的嗜盐菌LMZ2作为研究对象，分别对菌株进行了形态学、生理生化和分子生物学鉴定，并测定了生长曲线，pH曲线及碳酸酐酶曲线，设置不同镁钙比(分别为0、3、5、7、9)，以嗜盐菌LMZ2为工作菌株，在25%盐度，pH 7.2条件下进行了较系统的碳酸盐微生物诱导矿化实验。结果表明，嗜盐菌LMZ2 (Genbank登录号：MH430039)为革兰氏阴性菌，不产芽孢，产氨气，产接触酶，经综合鉴定LMZ2为一株以色列色盐杆菌(Chromohalobacter israelensis)。LMZ2在150小时后OD值可达到0.8，在225小时pH上升至8.0左右，不产碳酸酐酶。镁钙比为0时只有方解石，镁钙比在3、5、7可以诱导出组合为单水方解石、富镁方解石和碳酸钙镁石等含镁碳酸盐矿物，镁钙比9时为单水方解石。当有镁离子存在的情况下，嗜盐菌诱导的矿物晶粒和结晶度更好。该研究表明极端嗜盐菌在高盐环境中和高镁因素叠加有力促进了含镁碳酸盐矿物和亚稳定碳酸盐矿物的生成，为解释地质记录中相关碳酸盐矿物的形成机理提供了重要的参考。

Abstract: Based on the salt mud samples collected from Yinjiashan Salt Farm in Jiaonan Qingdao. The standard method was used to screen 7 strains that could tolerate 25% salinity. A better-growing halophilic strain named LMZ2 was selected and carried out morphological, physiological and biochemical, and molecular biology identified. And the growth, pH changed and carbonic anhydrase curves were also tested and drawn. Then different magnesium-calcium ratios (0, 3, 5, 7, 9, respectively), LMZ2 halophilic bacteria, at 25% salinity, more systematic experiments of carbonate microorganism induced mineralization were carried out under pH 7.2 conditions. The results showed that strain LMZ2 of halophilic bacteria (Genbank No.: MH430039) is one kind of gram-negative bacteria, not producing spores, producing ammonia and contact enzymes, and therefore can be identified as Chromohalobacter israelensis. Chromohalobacter israelensis LMZ2 can reach up to 0.8 of OD600 value after 150 hours culture. However, at about pH 8.0 225 hours, it does not produce carbonic anhydrase. When the ratio of magnesium to calcium is 0, there is only calcite. When the ratio of magnesium to calcium is 3, 5, and 7, it can induce a combination of magnesium-containing carbonate minerals such as monohydrate calcite, magnesium-rich calcite, and magnesia carbonate. When the ratio of magnesium to calcium is 9, it is single Monohydrocalcite. In the presence of magnesium ions, the mineral grains and mineralization degree induced by halophilic bacteria are better. This study shows that extreme halophilic bacteria can positively promote the formation of magnesium-bearing carbonate minerals and unstable calcium carbonate minerals in high salt environment. This study provides an important reference for explaining the formation mechanism of related carbonate minerals in geological records.