一株产脂肪酶嗜盐菌的鉴定及耐盐机理

Identification of a Lipase Producing Halophilic Strain and Its Halophilic Mechanism

从采自内蒙古锡林浩特地区盐湖的样品中筛选到产脂肪酶嗜盐菌JNPH-3,该菌株可在含有1.5～5mol/L NaCl的培养基上生长,最适生长温度45℃,最适pH7～9.5.经形态学分析、生理生化实验及16SrDNA鉴定,JNPH-3菌株为Halorubrum aidingense,属于极端嗜盐菌.JNPH-3菌株在生长过程中专一性依赖Na+,对Cl-依赖性较小,K+浓度变化对菌体生长无明显影响.高效液相色谱分析表明,JNPH-3菌株在液体复合培养基中能够产生四氢嘧啶,且与环境中盐浓度呈负相关,说明JNPH-3体内除存在产生四氢嘧啶的机制来维持渗透平衡,还有其它机制来维持细胞正常生长.

A novel halophile strain producing lipase,named as JNPH-3,was screened from the samples isolated from hypersaline lakes in Inner Mongolia.It could grow in the medium containing1.5～5 mol/L NaCl,and optimally at temperature of 45 ℃ and pH of 7～9.5.It was identified as Halorubrum aidingense,belonging to the group of extreme halophiles,by its morphological,physiological and biochemical characters,and 16S rDNA sequences.The growth of JNPH-3 specifically depended on anion Na＋,but other anion and cation ions such as Cl-,Br-,I-,K＋,Li＋ had no obvious effect on its growth.It was also found that JNPH-3 could produce ectoine in the complex medium.However,the yield of ectoine was negatively related with the concentration of environmental NaCl,which was not consistent with the well-known mechanism of halophile strain,suggesting that JNPH-3 had another mechanism to support its growth,besides the mechanism of producing ectoine to keep its osmotic equilibrium.