生物表面活性剂鼠李糖脂对水体中石油烃降解的促进作用

Enhancement of Rhamnolipid Biosurfactant for Biodegradation of Petroleum Hydrocarbons in Water

从被含油废水污染的土壤中筛选得到4株能利用柴油为唯一碳源生长的杆菌(X1,X2,X3和X4),经鉴定,这4株菌分别属于沙雷铁氏菌属(Serratiasp.)、不动菌属(Acinetobactersp.)、芽孢杆菌属(Bacillussp.)和氮单胞菌属(Azomonassp.).其中,菌株X4于32℃摇床培养28d后对柴油的降解率达62%,而在相同条件下,添加生物表面活性剂鼠李糖脂后柴油的降解率提高了26%.平板菌落计数结果表明,鼠李糖脂能促进菌的生长,生物量明显增多.对菌株降解反应的动力学研究进一步验证了鼠李糖脂对菌株X4降解石油烃的促进作用,添加了鼠李糖脂的样品组比对照组的半衰期缩短了近1倍.通过设计正交实验,本文研究了培养温度、培养时间、鼠李糖脂的添加量及石油烃的浓度等主要环境因子对水体中石油烃降解的影响.实验结果表明,影响水体中石油烃降解的主导因子是培养时间,其次是培养温度、石油烃的浓度和鼠李糖脂的添加量.

Four bacterial strains （ X1, X2, X3 and X4）using diesel oil as sole carbon source were screened from soil, which was polluted by oily wastewater, and they were identified as Serratia sp. , Acinetobacter sp. , Bacillus sp. and Azomonas sp. , respectively. After strain X4 was cultured for 28 d with a rotary shaker at 32 ℃ , the degradation rate of diesel oil by the strain reached 62% and also the biodegradation of diesel oil was significantly enhanced by the amendment of rhamnolipid biosurfactant, which indicated that rhamnolipid increased microbial biomass and the biodegradation of diesel oil was 26% higher than that without rhamnolipid. Adding rhamnolipid could shorten the half life by nearly 50%. By designing orthogonal tests, the effects of four major factors, culture temperature, culture time, dosage of rhamnolipid and concentration of petroleum hydrocarbons, on the degradation rate of hydrocarbons in water were studied.