一株糖脂表面活性剂产生菌的筛选及干酪根降解

【目的】从油页岩环境中筛选可降解油页岩干酪根的产生物表面活性剂菌株。【方法】从抚顺油页岩矿废水样品中用血平板法初筛,排油圈法、乳化法和表面张力法复筛,获得产生物表面活性剂菌株。对目标菌株进行生理生化鉴定、16S r RNA基因序列和系统发育分析,用薄层色谱鉴定其发酵液表面活性成分,优化产表面活性剂的培养条件,初步考察其对油页岩干酪根的降解能力。【结果】筛选到一株产糖脂表面活性剂菌株B-1,初步鉴定为Pseudomonas sp.,该菌株有良好的排油和乳化能力以及较低的表面张力,可利用烷烃、不饱和脂肪酸和糖类作为碳源。在30-34°C范围内添加0.3%Na Cl的葡萄糖培养基(p H 7.0)中该菌生长旺盛,发酵液表面张力最低为27 m N/m。菌株B-1在添加一定量葡萄糖的无机盐培养基中作用30 d后对干酪根的降解率为2.85%,高于不添加葡萄糖无机盐培养基对照组的降解率(1.04%)。【结论】菌株B-1是一株性能良好的产糖脂表面活性剂细菌,有降解干酪根的潜力。

Screening of a glycolipid biosurfactant-producing strain for kerogen biodegradation

Objective] Biosurfactant-producing strains were screened from an oil-shale environment for the biodegradation of kerogen in oil shale. Methods] Wastewater samples of the Fushun oil-shale mine were collected and used for the primary screening of biosurfactant-producing strains using the blood-agar plate method. Oil spreading, emulsification activity, and surface tension methods were further used to re-screen the biosurfactant-producing strains. The target strain was identified by 16S rRNA gene sequencing and phylogenetic analysis, as well as by determining its physiological and biochemical characteristics. Surface-active components in the zymotic fluid of the target strain were analyzed by thin-layer chromatography. The culture conditions were optimized for biosurfactant production by the target strain, and its biodegradation of oil-shale kerogen was examined preliminarily. Results] A glycolipid biosurfactant-producing strain, B-1, was screened and identified preliminarily as a Pseudomonas sp., and it showed the advantages of good oil displacement and emulsifying ability, and low surface tension. Strain B-1 used alkanes, unsaturated fatty acids, and carbohydrates as carbon sources. In a glucose-containing culture medium (pH 7.0) with 0.3% NaCl, strain B-1 grew well at 30?34 °C, and the surface tension of the zymotic fluid exhibited its lowest value (27 mN/m). After 30 d, the kerogen degradation rate of strain B-1 in the glucose-containing medium was 2.85%, compared with 1.04% in a control medium without glucose. Conclusion] Strain B-1 is a good glycolipid biosurfactant-producing bacterium with the potential to degrade kerogen.