土壤微生物对苯的降解研究

使用大庆油田石油污染土壤中分离出优势菌种(革兰氏阴性G^-、黄杆菌属Flavobacterium),在实验室可控条件下,研究了该菌种对苯的降解规律和特点.研究发现:微生物对苯浓度耐受范围8.8～17.6 mg·L^-1,大于17.6mg·L^-1时,对该菌株产生明显的抑制作用.降解体系在pH为6.5～7.0之间达到对苯的较高降解水平,最佳降解率出现在苯初始浓度7.04～13.2mg·L^-1之间;苯在微生物细胞内外的浓度变化趋势呈现一致.-lgP(P为有机溶剂苯在细胞膜和水相中的分配系数的比值)的变化能够较好的表征苯在微生物细胞内外的降解趋势和毒性变化;当体系中苯的初始浓度大于8.8mg·L^-1时,苯的降解率与P值变化趋于一致.

Study on Benzene Degraded by Soil Microorganism

The experiments were made in laboratory to analyze the characteristics and principle of benzene's biodegradation using the microorganism (G-, Flavobacterium) taken from Daqing oil fields. Results show that the maximal concentration of benzene, which microorganisms could endure is between 8.8 mg x L(-1) and 17.6 mg x L(-1); microorganisms were inhibited as benzene's concentration was beyond 17.6 mg x L(-1). Trends of benzene's concentration in and out of microorganism's cell are almost same; the biodegradation could be achieved efficiently as the pH range of 6.5 - 7.0 and benzene initial concentration range of 7.04 - 13.2 mg x L(-1). Change of - lgP (P is the distributive ratio of benzene in membrane and water) could be illustrated the trends of toxicity and degradation of benzene in and out of microorganism's cell; the biodegradation rate varied simultaneously with the change of P as initial concentration of benzene was beyond 8.8 mg x L(-1).