The contamination of soils by oily compounds has several environmental impacts, which can be reversed through bioremediation, using biosurfactants as auxiliaries in the biodegradation process. In this study, we aimed to perform ex situ bioremediation of biodiesel-contaminated soil using biosurfactants produced by Bacillus methylotrophicus. A crude biosurfactant was produced in a whey-based culture medium supplemented with nutrients and was later added to biodiesel-contaminated clayey soil. The produced lipopeptide biosurfactant could reduce the surface tension of the fermentation broth to 30.2 mN/m. An increase in the microbial population was observed in the contaminated soil; this finding can be corroborated by the finding of increased CO₂ release over days of bioremediation. Compared with natural attenuation, the addition of a lower concentration of the biosurfactant (0.5% w/w in relation to the mass of diesel oil) to the soil increased biodiesel removal by about 16% after 90 days. The added biosurfactant did not affect the retention of the contaminant in the soil, which is an important factor to be considered when applying in situ bioremediation technologies.

油性化合物对土壤的污染具有多种环境影响，可以通过使用生物表面活性剂作为生物降解过程中的助剂，通过生物修复来逆转。在这项研究中，我们旨在使用甲基芽孢杆菌产生的生物表面活性剂对生物柴油污染的土壤进行异位生物修复。在添加了养分的乳清基培养基中生产粗制生物表面活性剂，然后将其添加到受生物柴油污染的黏土中。产生的脂肽生物表面活性剂可将发酵液的表面张力降低至30.2 mN / m。在受污染的土壤中观察到微生物种群的增加；CO ₂增加的发现可以证实这一发现经过数天的生物修复释放。与自然衰减相比，向土壤中添加较低浓度的生物表面活性剂（相对于柴油质量为0.5％w / w）在90天后将生物柴油去除量提高了约16％。添加的生物表面活性剂不会影响污染物在土壤中的保留，这是应用原位生物修复技术时要考虑的重要因素。