产表面活性剂降解石油菌株产物性质及降解性能研究

微生物是组成生态系统的重要成员，在污染物去除中发挥着重要作用，是生物修复中的主力，然而在石油污染修复过程中，石油烃的疏水性会限制微生物对石油的降解，但一些微生物的细胞代谢物即生物表面活性剂，它是微生物在一定条件下代谢分泌产生的具有一定表面活性，集亲水基和疏水基结构于一分子的两亲性化合物，可以促进油的乳化，提高油的分散程度，增大菌株和油珠的接触机会，促进对石油烃的吸收和降解。在实验室分离得到了7株产表面活性剂石油降解菌株，经分子鉴定可知菌1和菌2都为粘质沙雷氏菌Serratia marcescens，菌3为居植物柔武氏菌Raoultella planticola，菌4，菌6和菌7都为克雷伯氏菌Klebsiella variicola，菌5为蜡状芽孢杆菌Bacillus cereus。主要研究了它们的生长与表面活性剂物质分泌状况的关系，发现随着时间增加，OD值随之增大，表面张力呈现下降趋势；并对菌株产物进行提取和薄层层析，离子型分析和红外光谱分析，初步判断其产物均为阴离子糖脂类；通过pH，初始油质量浓度，接种量和盐度4个单因素的变化研究菌1粘质沙雷氏菌，菌3居植物柔武士菌，菌5蜡状芽孢杆菌和菌6克雷伯氏菌对石油类物质降解能力，发现菌3居植物柔武氏菌和菌5蜡状芽孢杆菌降解性能较好；通过响应曲面法优化蜡状芽孢杆菌的降解条件，得出其最佳降解条件为pH为5.02，油质量浓度为3 g·L-1，接种量为1199.98μL，盐度为0.5 g·L-1时，在此条件下，菌株对石油的降解率为66.94%。

The Research on products properties and oil degradation capability of strains producing surfactant

Microorganism, which is the main force in bioremediation, is an important member of ecosystem, and it plays an important role in pollutant removal. The hydrophobic of petroleum hydrocarbon may limit the degradation of organisms in the repair process of oil pollution. Some microbial cells metabolites, namely biosurfactants, which is secreted by microorganism under certain conditions and is amphiphilic compounds with combined structure of hydrophilic group and hydrophobic group in a molecule. These biosurfactants can promote oil emulsion, improve the dispersion of the oil, increase the contact opportunity between strain and oil bead and promote absorption and degradation of petroleum hydrocarbons. Seven oil degradation strains producing surfactants were isolated, of which bacteria 1 and bacteria 2 are Serratia marcescens, bacteria 3 is Raoultella planticola, bacteria 4, bacteria 6 and bacteria 7 are Klebsiella variicola, bacteria 5 is Bacillus cereus. The relationship between bacteria growth and the surfactant material secretion was studied and found that OD value increased while surface tension decreased with the increase of time. Extraction products of strains were examined by thin-layer chromatography, ion-type analysis and IR spectroscopy. Anion Glycolipid was found as the main components. Oil degradation capabilities of different strains were measured considering four single factor, pH, initial oil mass concentration, inoculation amount and salinity. Bacteria Raoultella planticola and bacteria Bacillus cereus had better degradation performance. Response surface methodology was used to study on Bacillus cereus degradation conditions. Its optimum degradation conditions were pH of 5.02, oil mass concentration of 3 g·L-1, inoculation amount 1 199.98μL, salt mass concentration of 0.5 g·L-1. In this condition, the oil degradation rate was 66.94%.