低温1,2,4-TCB降解菌的选育、降解特性及邻苯二酚1,2-双加氧酶基因表达水平

Isolation,degradation characteristics and catechol 1,2 dioxygenase gene expression level of 1,2,4-TCB degrading bacterium under low temperature

从长期受1,2,4-三氯苯(1,2,4-TCB)污染的地下水中筛选出一株低温寡营养降解菌A2,对A2菌进行革兰氏染色鉴定和16S rDNA鉴定,研究了不同pH、温度、盐度等因素对A2菌降解1,2,4-TCB效果以及对邻苯二酚1,2-双加氧酶基因表达的影响,并进行了正交实验。结果表明,A2菌为革兰氏阴性短杆细菌,初步鉴定为假单胞菌;在pH值为7、培养温度30℃、盐度0.8%、培养时间6 d时,A2菌对1,2,4-TCB降解效果最好,降解率达到88.14%,同时该条件下邻苯二酚1,2-双加氧酶基因相对表达水平最高;培养温度为10℃时,A2菌对1,2,4-TCB降解率可达到85.3%,同时邻苯二酚1,2-双加氧酶基因也有较高的相对表达水平。以上结果说明,将A2菌应用于低温寡营养地下水的生物修复是可能的。

An oligotrophic degrading bacterium named strain A2 was screened trom groundwater long-term contaminated by 1, 2, 4-TCB under low temperature condition, strain A2 was identified by gram stain and 16S rDNA sequence, the impacts of different pH, temperature, salinity on degradation effect and catechol l ,2 dioxygenase gene expression level were studied, and orthogonality experiment was carried out. The results showed that strain A2 was gram negative short rods, and was identified as pseudomonas preliminarily. The degrading effect of strain A2 on 1,2,4-TCB and catechol 1,2 dioxygenase gene expression level showed best under the conditions： pH of 7, cultivation temperature of 30℃ , salinity of 0.8% , cultivation time of 6 days, and the degrading rate could reach 88.14%. The degrading rate of 1,2,4-TCB by strain A2 could reach 85.3% at 10℃ , and cateehol 1,2 dioxygenase gene expression level also showed a relative high expression level. This research demonstrated that it is possible to apply strain A2 in the bioremediation of oligotrophic groundwater under low temperature condition.