The biosurfactant produced by Candida sphaerica in a fermentor containing 5% vegetal oil refinery waste and 2.5% was tested in the removal of motor oil from soils and seawater. In kinetic assays, the isolated biosurfa...The biosurfactant produced by Candida sphaerica in a fermentor containing 5% vegetal oil refinery waste and 2.5% was tested in the removal of motor oil from soils and seawater. In kinetic assays, the isolated biosurfactant removed more than 86% of the motor oil adsorbed to clay, silty and sandy soils at the critical micelle concentration （CMC）. Static removal tests performed in glass columns demonstrated that the crude biosurfactant was able to remove 75% and 92% of the oil contained in clay and silty soil, respectively, whereas the isolated biosurfactant at its CMC removed 50% of the oil from sandy soil. In the washing of hydrophobic compound on a porous surface, the removal rate was 60%. The biosurfactant also proved to be efficient in detergency tests since the crude surfactant removed 41% of motor oil from contaminated cotton cloth. In tests carried out with seawater, the crude biosurfactant showed an oil spreading efficiency of 75% in both screening dispersion test and oil displacement efficiency methods. Regarding the swirling bottle test, the dispersion rate was 72% for the isolated biosurfactant at a concentration twice the CMC. The biosurfactant studied demonstrated potential for application as an adjuvant in biotechnological processes for environmental decontamination.展开更多
文摘The biosurfactant produced by Candida sphaerica in a fermentor containing 5% vegetal oil refinery waste and 2.5% was tested in the removal of motor oil from soils and seawater. In kinetic assays, the isolated biosurfactant removed more than 86% of the motor oil adsorbed to clay, silty and sandy soils at the critical micelle concentration （CMC）. Static removal tests performed in glass columns demonstrated that the crude biosurfactant was able to remove 75% and 92% of the oil contained in clay and silty soil, respectively, whereas the isolated biosurfactant at its CMC removed 50% of the oil from sandy soil. In the washing of hydrophobic compound on a porous surface, the removal rate was 60%. The biosurfactant also proved to be efficient in detergency tests since the crude surfactant removed 41% of motor oil from contaminated cotton cloth. In tests carried out with seawater, the crude biosurfactant showed an oil spreading efficiency of 75% in both screening dispersion test and oil displacement efficiency methods. Regarding the swirling bottle test, the dispersion rate was 72% for the isolated biosurfactant at a concentration twice the CMC. The biosurfactant studied demonstrated potential for application as an adjuvant in biotechnological processes for environmental decontamination.
