Civil and Environmental Engineering, Faculty of Engineering and Architecture, University of Passo Fundo, Campus I, Building L1, BR 285, km 171, Neighborhood São José, Mailbox 611, Passo Fundo, RS, CEP: 99052-900, Brazil.
Environmental Engineering Course, Faculty of Engineering and Architecture, University of Passo Fundo, BR 285, km 171, Passo Fundo, RS, Brazil.
Biodegradation. 2021 Aug;32(4):389-401. doi: 10.1007/s10532-021-09944-z. Epub 2021 Apr 17.
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 CO 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.
油类化合物污染土壤会造成多种环境影响，而这些影响可以通过生物修复加以逆转，具体做法是在生物降解过程中使用生物表面活性剂作为助剂。本研究旨在利用甲基营养型芽孢杆菌生产的生物表面活性剂，对受生物柴油污染的土壤进行异位生物修复。生物表面活性剂是在添加了营养物质的乳清培养基中生产的粗制品，随后被添加到受生物柴油污染的粘性土壤中。所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。受污染土壤中的微生物种群数量增加，这一点可以通过生物修复过程中 CO2 释放量的增加得到证实。与自然衰减相比，在 90 天内，将较低浓度的生物表面活性剂（相对于柴油质量的 0.5%w/w）添加到土壤中，可使生物柴油的去除率提高约 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，这是在应用原位生物修复技术时需要考虑的一个重要因素。
