产表面活性剂石油降解菌的筛选及发酵条件优化

Isolation of oil-degrading bacteria with biosurfactant production and its fermentation condition optimization

从胜利油田受石油污染的土壤中筛选出能产生表面活性剂的石油降解菌,对其进行初步鉴定,并探讨了其降解原油的性能与生长条件。经过富集培养、平板筛选、血平板筛选、排油圈测定,成功分离筛选出1株产生表面活性剂的石油降解菌株X-1。经形态观察、生理生化试验和16S rDNA序列分析等鉴定其为芽孢杆菌属(Bacillus sp.),培养6 d时原油降解率为30.04%。通过硅胶板薄层层析初步判定表面活性剂粗品中含有脂肽、脂蛋白类物质。菌株生长的最适温度为32℃,最适pH为7.0,最适盐度为2 g.L-1 NaCl,最佳碳源为淀粉,最佳氮源为蛋白胨。

An oil-degrading bacteria with biosurfactant production was isolated from petroleum-contaminated soil of Shengli Oil Field in Shandong Province, and preliminary identification was conducted on it. We also studied its degradation characteristics and growth conditions. By enrichment cultivation, plate screening, blood plate screening and determination of oil discharge circle, we successfully isolated strain X-1. According to its morphological, physiological, biochemical features and 16S rDNA sequence analysis, strain X-1 was identified as Bacillus sp. Its oil-degrading rate was 30.04% after incubating for six days. With preliminary judgement of silica gel thin layer chromatography, crude biosurfactant contains lipopeptid and lipoproteins. Its optimal conditions for growth were 32 ℃, pH 7.0 and 2 g·L-1 NaCl,the starch was the best carbon source,whereas the peptone was the best nitrogen source.