汽油降解菌的分离及降解研究

Studies on Isolation of Gasoline Degrading Bacteria and Its Degrading Properties

从泄漏污染的加油站土壤中筛选出对汽油具有较强降解能力的菌株,研究该菌株最适宜的生长条件,探讨紫外线诱导及投加表面活性剂等强化手段对该菌株降解汽油的影响.结果表明:①通过富集培养的方法分离得到的菌株Q18,经形态特征及生理生化特征鉴定,初步确定其为红球菌(Rhodococcussp.).②菌株Q18在培养液中适宜生长的温度,pH和底物质量浓度分别为35℃,6.0和1 000 mg/L.③通过紫外线照射诱变后的菌株降解能力强于原始菌株,且15 W紫外灯对菌株的诱变效果优于30 W;氯化锂单独诱变效果不明显;经紫外灯照射和氯化锂复合诱变的菌株QY4对汽油的降解率达到了52.2%,在所有诱变菌中最高,效果最显著.④表面活性剂能增强汽油的生物可利用性,强化菌株Q18对汽油的降解,但阴离子和非离子的混合表面活性剂SDS+TX-100和SDS+TW-80比单一表面活性剂更能有效提高菌株Q18对汽油的降解率.

Bacterial strains capable of degrading gasoline from gas station leaking contaminated soils were isolated, to study the effects of culture conditions in vitro, breeding by ultraviolet radiation mutation and enhancement of gasoline degradation by adding surfactant. The results show：①The bacterial strains Q18 isolated by enrichment culture were identified as Rhodococcus sp., according to their morphological character and physiological-biochemical character. ② The optimal pH, temperature and gasoline mass concentration for growth of bacteria Q18 are 6.0, 35℃ and 1 000 mg/L, respectively.③ The mutants by ultraviolet radiation treatment had greater degrading efficiency than the original ones, with 15 W ultraviolet light having better mutation effect on the strains than 30 W ultraviolet light. The mutation effect of lithium chloride by itself was not obvious, but the bacterial strains QY4 by ultraviolet radiation-lithium chloride complex treatment had degrading efficiency of 52.2%, being the highest among the mutated strains.④ All the surfactants could increase the bioavailability of gasoline and enhance the degradability of gasoline by bacterial strains Q18, but compared with single surfactant, the greater enhancement of the degradation of gasoline by Rhodococcus sp. were observer by mixed surfactant such as SDS ＋ TX-100 and SDS ＋ TW-80.