一株五溴联苯醚(BDE-99)降解菌的分离、鉴定及降解特性

采用梯度压力驯化法从高海拔地区土壤样品中分离到1株能以BDE-99作为碳源生长的细菌菌株，命名为BHS-4，通过生理生化及对16S rDNA扩增，T/A克隆后测序鉴定，并进一步分析初始pH、温度、碳源、细胞表胞疏水性（MATH法）及共存重金属离子对菌株降解效果的影响。结果表明：菌株BHS-4与产碱杆菌属Alcaligenes cupidus同源性为99%。菌株降解BDE-99最适pH和温度分别为8.0、20 ℃，经11 d培养后，对浓度0.4 mg·L-1的BDE-99，降解率达86.1%，在15~20 ℃范围具有较高降解率。降解特性研究结果显示，乳糖、麦芽糖和葡萄糖的添加促进了BHS-4对BDE-99的降解，而淀粉和乙酸钠添加对降解率产生了显著抑制作用（P4NO3的添加，使细胞表面疏水率（CSH）增加了49.5%，CSH与降解率呈极显著正相关（r=0.99， P2+、Zn2+在0.1~0.3 mg·L-1浓度下促进BDE-99降解；Cr6+在0.1~0.6 mg·L-1范围内对降解作用影响表现为先抑制、再促进、最后抑制。菌株BHS-4能在较低温度下对BDE-99进行高效降解且对Cu2+、Zn2+、Cr6+具有一定的耐性，可应用于低温地区BDE-99的生物处理，同时可为进一步研究低温条件下BDE-99生物降解的代谢途径和机理提供一定的基础资料。

Isolation,identification and degradation characteristics of decabromo diphenyl ethers (BDE-99)-degrading strain

A gram-negative bacterium capable of aerobically transforming BDE-99 was isolated from soil samples from a high altitude area by the gradient pressure acclimatization technique. The bacterial strain named BHS-4, was identified by physiological and biochemical characteristics and 16S rDNA sequence analysis. The factors affecting BDE-99 degradation, including initial pH of medium, culture temperature, carbon sources, cell surface hydrophobicity (MATH), and heavy metals, were then examined. The results showed that BHS-4 showed 99% homology with Alcaligenes cupidusbased on 16S rDNA sequence analysis. The optimal growth pH and temperature for BHS-4 were 8.0 and 20℃, respectively. BHS-4 could degrade BDE-99 effectively from 15 to 20℃. Under optimal conditions, BHS-4 could effectively degrade 86.1% of BDE-99 (0.4 mg·L-1) after 11 days incubation. Lactose, maltose, and glucose increased the degradation rate whereas amylum and sodium acetate significantly inhibited degradation (P4NO3.CSH and degradation rate were positively correlated (r=0.99, P2+ and Zn2+ at low concentrations from 0.1 mg·L-1 to 0.3 mg·L-1 improved the degradation of BDE-99. BDE-99 degradation rate showed an orderly trend of decrease, increase, and decrease under the experimental Cr6+concentration of 0.1 to 0.6 mg·L-1. BHS-4 could degrade BDE-99 at a relatively low temperature with high efficiency and tolerated Cu2+, Zn2+, and Cr6+ to some extent. Hence, the strain BHS-4 can be applied in BDE-99 biodegradation treatment systems in cold conditions. It also provides a scientific basis to further understand the metabolic pathways and mechanism of BDE-99 biodegradation.