Department of Environmental Sciences, University of Milano-Bicocca, Piazza della Scienza 1, 20126 Milano, Italy.
Bioresour Technol. 2012 Mar;108:245-51. doi: 10.1016/j.biortech.2012.01.005. Epub 2012 Jan 10.
The aims of this work were the characterisation and the evaluation of potential environmental applications of the bioemulsifiers produced by Variovorax paradoxus 7bCT5. V. paradoxus 7bCT5 produces a mixture of high molecular weight polysaccharides. The extracellular bioemulsifiers were able to produce a thick stable oil/water emulsion and maintained the emulsification activity after boiling and at low temperatures. Environmental behavior and impact of bioemulsifiers release were assessed by evaluating biodegradability, toxicity and soil sorption. Respirometric tests showed that moderate biodegradability occurred by soil bacterial inoculum. Furthermore, the produced compounds did not show any toxic properties through different ecotoxicological tests. The K(d) values ranged from 1.3 to 7.3 L/kg indicating a high sorption affinity of the bioemulsifier molecules to soil particles. The soil sorption affinity likely affected the bioemulsifier ability to remove hydrocarbons from contaminated soils. In fact, V. paradoxus 7bCT5 bioemulsifiers significantly increased the removal of crude-oil from sandy soil compared to water.
本工作的目的是对副球菌 7bCT5 产生的生物乳化剂的特性及其在环境中的潜在应用进行评估。副球菌 7bCT5 产生高分子量多糖混合物。胞外生物乳化剂能够产生厚而稳定的油/水乳液，并在煮沸和低温下保持乳化活性。通过评估生物乳化剂的生物降解性、毒性和土壤吸附性来评估其环境行为和释放的影响。呼吸计测试表明，土壤细菌接种物可适度生物降解。此外，通过不同的生态毒理学测试表明，所产生的化合物没有任何毒性。K(d) 值范围为 1.3 到 7.3 L/kg，表明生物乳化剂分子对土壤颗粒具有高的吸附亲和力。生物乳化剂对土壤中碳氢化合物的去除能力可能受到土壤吸附亲和力的影响。事实上，与水相比，副球菌 7bCT5 生物乳化剂显著提高了从沙土中去除原油的能力。
