In industrial wastewater treatment, organic pollutants are usually removed by in-situ microorganisms and exogenous bactericides. Benzo [a] pyrene (BaP) is a typical persistent organic pollutant and difficult to be removed. In this study, a new strain of BaP degrading bacteria Acinetobacter XS-4 was obtained and the degradation rate was optimized by response surface method. The results showed that the degradation rate of BaP was 62.73% when pH= 8, substrate concentration was 10 mg/L, temperature was 25 °C, inoculation amount was 15% and culture rate was 180 r/min. Its degradation rate was better than that of the reported degrading bacteria. XS-4 is active in the degradation of BaP. BaP is degraded into phenanthrene by 3, 4-dioxygenase (α subunit and β subunit) in pathway Ⅰ and rapidly forms aldehydes, esters and alkanes. The pathway Ⅱ is realized by the action of salicylic acid hydroxylase. When sodium alginate and polyvinyl alcohol were added to the actual coking wastewater to immobilize XS-4, the degradation rate of BaP was 72.68% after 7 days, and the removal effect was better than that of single BaP wastewater (62.36%), which has the application potential. This study provides theoretical and technical support for microbial degradation of BaP in industrial wastewater.

在工业废水处理中，有机污染物通常通过原位微生物和外源杀菌剂去除。苯并[a]芘（BaP）是一种典型的持久性有机污染物，难以去除。本研究获得了一株BaP降解菌Acinetobacter XS-4新菌株，并采用响应面法对其降解速率进行了优化。结果表明，当pH=8、底物浓度为10mg/L、温度为25℃、接种量为15%、培养速率为180r/min时，BaP的降解率为62.73%。其降解率优于报道的降​​解菌。XS-4在 BaP 的降解中具有活性。BaP在途径Ⅰ中被3, 4-双加氧酶（α亚基和β亚基）降解为菲，并迅速形成醛、酯和烷烃。途径Ⅱ是通过水杨酸羟化酶的作用实现的。在实际焦化废水中加入海藻酸钠和聚乙烯醇固定化XS-4时，7天后BaP的降解率为72.68%，去除效果优于单一BaP废水（62.36%），具有应用潜力。该研究为工业废水中BaP的微生物降解提供了理论和技术支持。