甲苯降解光合细菌的分离、鉴定与降解条件优化

Screening,Identification and Bio-degradation Characters of a Toluene Degradable Bacteria

配制以甲苯为单一碳源的培养基,通过厌氧条件下的驯化、富集及双层平板分离,从石油化工污泥中筛选出一株对甲苯有较强降解能力的兼氧光合细菌菌株AQ-02。该菌株在54h内能完全降解100mg/L的甲苯(28℃、15%接种量),通过形态特征分析、16s RNA分子鉴定技术,鉴定为荚膜红细菌属(Rhodobacter Capsulatus),其在甲苯初始浓度为100~250mg/L、温度20~30℃、pH值6~8范围内能有效净化甲苯,48h甲苯降解率为26.8%~76.0%。通过正交实验分析影响菌株降解效率的因素结果表明:温度、初始甲苯浓度、pH值均对降解甲苯效果有显著影响。影响因子按重要程度排序为:温度>pH>甲苯浓度>接种量。菌株降解甲苯最优条件为:温度30℃以上、中性或弱碱性环境、甲苯初始浓度100 mg/L和15%的菌种接种量。其对苯系物中的二甲苯具有一定降解效果,能在60h内降解浓度为100mg/L的二甲苯。实验可为苯系物污染废水的生物治理提供高效、低能耗、无二次污染的功能微生物材料。

A strain AQ-02 with a strong ability to degrade toluene was selected from the sludge of a petrochemical plant.Based on morphological characteristics and molecular identification,the strain was identified as Rhodobacter Capsulatus.The degradation rate of toluene in 48h is 26.8%~76.0%.Analysis of factors affecting the degradation efficiency of strains by orthogonal experiments showed that temperature,initial toluene concentration,and pH value all have significant effects on the degradation of toluene.The impact factors are ranked in order of importance:temperature>pH>toluene concentration>inoculation amount.The optimal conditions for the strain to degrade toluene are:temperature above 30℃,neutral or weakly alkaline environment,initial concentration of toluene 100 mg/L and 15%of the bacterial inoculum.It has a certain degradation effect on xylene in benzene series,and can degrade xylene with a concentration of 100mg/L within 60 hours.The experiment can provide functional microbial materials with high efficiency,low energy consumption and no secondary pollution for the microbial treatment of benzene series polluted wastewater.