利用低温循环水槽模拟地下水环境温度（10℃），以辽阳石化公司含油废水处理好氧池中活性污泥为菌株来源、苯系物为唯一碳源，经污泥驯化和菌株富集、分离、纯化分离出5株耐低温BTEX降解菌。经16S rRNA基因分析并结合其形态学和生理学特性，鉴定菌株DS1、菌株DS3属于假单胞菌属（Pseudomonas sp.）；菌株DS2和菌株DS4为芽孢杆菌属（Bacillus sp.）；菌株DS5属于葡萄球菌属（Staphylococcus sp.）。低温条件下，优选得到降解能力高的优势菌株DS4，其对邻、间、对二甲苯的降解率达到96.41%，对乙苯的降解率为95.38%，对甲苯的降解率为80.37%，对苯的降解能力最低，为63.92%。

Cryogenic circulating flume is employed to simulate the environment temperature (10℃) of groundwater, and the strain comes from the activated sludge generated in aerobic tank for oily wastewater treatment in PetroChina Liaoyang Petrochemical Company.Benzene-toluene-ethylbenzene-xylene (BTEX) is taken as carbon source.Five strains, which can degrade BTEX and are resistant to low temperature, are isolated through domesticating the activated sludge, and enriching, separating and purifying bacteria.Through analyzing 16S rRNA gene and combining with morphological and physiological characteristics, DS1 and DS3 are identified as strains of Pseudomonas sp., DS2 and DS4 are identified as Bacillus sp.and DS5 belongs to Staphylococcus sp.Under low temperature conditions, DS4 is screened out as the superior bacterium with higher degradation ability.The degradation rate of o-xylene, m-xylene and p-xylene by DS4 reaches 96.41%, that of ethylbenzene, toluene and benzene is 95.38%, 80.37% and 63.92%, respectively.