Abstract：
This study aimed to reveal that the effect of biosurfactant on the dispersion and degradation of crude oil. Whole genome analysis showed that Pseudomonas aeruginosa GB-3 contained abundant genes involved in biosurfactant synthesis and metabolic processes and had the potential to degrade oil. The biosurfactant produced by strain GB-3 was screened by various methods. The results showed that the surface tension reduction activity was 28.6 mN·m-1 and emulsification stability was exhibited at different pH, salinity and temperature. The biosurfactant was identified as rhamnolipid by LC-MS and FTIR. The fermentation conditions of strain GB-3 were optimized by response surface methodology, finally the optimal system (carbon source: glucose, nitrogen source: ammonium sulfate, C/N ratio:16:1, pH: 7, temperature: 30-35 °C) was determined. Compared with the initial fermentation, the yield of biosurfactant increased by 4.4 times after optimization. In addition, rhamnolipid biosurfactant as a dispersant could make the dispersion of crude oil reach 38% within seven days, which enhanced the bioavailability of crude oil. As a biostimulant, it could also improve the activity of indigenous microorganism and increase the degradation rate of crude oil by 10-15%. This study suggested that rhamnolipid biosurfactant had application prospect in bioremediation of marine oil-spill.
摘要：
本研究旨在揭示生物表面活性剂对原油分散和降解的影响。全基因组分析表明，铜绿假单胞菌GB-3含有丰富的参与生物表面活性剂合成和代谢过程的基因，具有降解油脂的潜力。通过多种方法筛选菌株GB-3产生的生物表面活性剂。结果表明，在不同pH下，表面张力降低活性为28.6mN·m-1，乳化稳定性良好，盐度和温度。通过LC-MS和FTIR鉴定生物表面活性剂为鼠李糖脂。采用响应面法对菌株GB-3的发酵条件进行了优化,最后是最优系统(碳源：葡萄糖，氮源:硫酸铵,测定C/N比：16：1，pH：7，温度：30-35°C）。与初始发酵相比，优化后，生物表面活性剂的收率提高了4.4倍。此外,鼠李糖脂生物表面活性剂作为分散剂可以使原油在7天内的分散率达到38％，提高了原油的生物利用度。作为一种生物兴奋剂，它还可以提高本地微生物的活性，并将原油的降解率提高10-15％。该研究表明鼠李糖脂生物表面活性剂在海洋溢油生物修复中具有应用前景。
