产表面活性剂石油降解菌的筛选鉴定及修复效能

SCREENING AND IDENTIFICATION OF SURFACTANT-PRODUCING PETROLEUM-DEGRADING BACTERIA AND THEIR REMEDIATION EFFICACY

以炼油厂周边土壤中筛选出的产表面活性剂石油降解菌为研究对象,探究其产生表面活性剂的发酵条件及对土壤的修复效果。根据血平板、排油圈实验选定1株优势产表面活性剂菌株,编号为M-8,经生理生化试验和16S rDNA序列分析鉴定其为蜡样芽孢杆菌(Bacillus cereus);通过TLC、红外光谱分析测定菌株M-8产生脂肽类表面活性剂;为使菌株产生更多的表面活性剂,采用Plackett-Burman和Box-Behnken实验对发酵条件进行优化。结果表明:在pH为8.15,蔗糖为21.8 g/L,磷源为12.33 g/L,发酵培养3 d条件下,菌株表面活性剂的产量可达到(1.305±0.05)g/L。在实验室模拟条件下,以石油降解率、脱氢酶活性及土壤呼吸强度为指标,测定处理48 d后对石油污染土壤的修复效果。结果表明:处理48 d后,添加菌株组石油去除率达到91.23%,且添加菌株的土壤脱氢酶活性及呼吸强度远高于未添加菌株的土壤。

The surfactant-producing petroleum degrading bacteria screened from the soil around the refinery were used to investigate the fermentation conditions of surfactant production and the remediation effect on the soil.A dominant surfactant-producing strain,numbered M-8,was selected based on blood plate and oil drainage circle experiments,and identified as Bacillus cereus by physiological and biochemical tests and 16S rDNA sequence analysis;the production of lipopeptide surfactant by strain M-8 was determined by TLC and infrared spectroscopy.To make the strain produce more surfactant,the Plackett-Burman and Box-Behnken experiments were used to optimize the fermentation conditions for more surfactant production.The experimental results showed that the surfactant production of the strain could reach(1.305±0.05)g/L at a pH value of 8.15,21.8 g/L of sucrose,12.33 g/L of phosphorus source,and 3 days of fermentation incubation.The remediation effect on petroleum-contaminated soil after 48 d of treatment was measured under simulated laboratory conditions,using petroleum degradation rate,dehydrogenase activity,and soil respiration intensity as the indicators.The results showed that the oil removal rate of the added strain group reached 91.23%after 48 days of treatment,and the soil dehydrogenase activity and respiration intensity of the added strain were much higher than those of the soil without added strain.