甾类化合物降解菌D61的分离鉴定及其降解特性

Isolation and degradation characteristics of steroid-degrading bacterial strain D61

从杂草土壤中分离得到利用甾类化合物作为唯一碳源的菌株D61．经16S rDNA多态性分析鉴定菌株D61为肠杆菌科哈夫尼菌属，在20～37℃、pH 2．0～9．0的环境中生长较好，无卡那霉素抗性．降解试验和荧光定量PCR试验结果表明，菌株D61可通过paaC基因的环氧化作用途径对甾类化合物进行降解转化，其对睾丸酮的降解能力与阳性对照菌睾丸酮丛毛单胞菌相似，对雌酮的降解能力明显优于睾丸酮丛毛单胞菌．

Bacteria that effectively degrades anthropogenic steriod merges to be an environmental friendly tool in pollution abatement.In this study, bacterial strain D61 was isolated from weed soil and fed on 0.2 mmol · L^-1 exogenous steroid as the only carbonsource, and followed by 16S rDNA polymorphism analysis to identify its species. The optimum growing condition was detected bygrowing the strain in ambient temperature between 15 ℃ and 37 ℃ under pH from 2 to 11. Futhermore, resistance of strain D61 toantibiotics and its degradation efficacy on steriod, inclduing testosterone, estradiol and oestrone, were evaluated. Results showedthat strain D61 belonged to genus Hafnia of family Enterobacteriaceae. Strain D61 favored growing condition of 20-37℃ and pH 2.0-9.0. Strain D61 showed no resistance to Kanamycin. Degradation experiment and quantitative PCR analysis showed that strain D61degraded steroids via epoxidation of Isaac gene. Degradation rate on testosterone was similar to that of strain Comamonas testosteronewhich was used as positive control, but was significantly higher than that of estrone.