中文摘要：

从天津大港油田原油污染的土壤中富集分离出一株能高效降解苯、甲苯、乙苯和二甲苯（BTEX）的菌株ustb-1,基于形态特征、生理生化、16SrRNA序列系统学分析,确定该菌株为Rhodococcus属。该菌株可在96h内将初始浓度1432.88mg/L的BTEX混合物降解99.63%。通过微量热技术研究不同降解程度的BTEX混合物对枯草芽孢杆菌生长代谢的毒性抑制作用,结果表明：降解之前的BTEX混合物对枯草芽孢杆菌比生长速率的抑制率为84.70%,而降解96h之后对其抑制率为17.03%,说明Rhodococcus.sp ustb-1能有效地降低BTEX混合物降解这类物质的毒性。

英文摘要：

Strain ustb-1 was isolated from the petroleum-contaminated soil,which could aerobically degrade benzene,toluene,ethylbenzene and xylene（BTEX）.Based on the morphological characteristics,physiological and biochemical characteristics and sequence analysis of 16S rRNA,the isolate was identified as Rhodococcus sp.With an initial concentration of 1432.88 mg/L,the total removal extent of BTEX mixture was 99.63% by Rhodococcus sp.ustb-1 within 96 h.Toxicity potential of BTEX prior and after biodegradation process was evaluated by determining the heat output of metabolism in Bacillus subtilis in LB medium by microcalorimetry.The BTEX toxic effects were significantly reduced in the biodegraded samples.