Saez Juliana Maria, Casillas García Verena, Benimeli Claudia Susana
Planta Piloto de Procesos Industriales Microbiológicos (PROIMI-CONICET), Avenida Belgrano y Pasaje Caseros, 4000 Tucumán, Argentina.
Ecotoxicol Environ Saf. 2017 Oct;144:351-359. doi: 10.1016/j.ecoenv.2017.06.026. Epub 2017 Jun 22.
Lindane is an organochlorine pesticide which persists in the environment and can cause serious health problems due to its chlorinated and hydrophobic nature. Microemulsions are isotropic and macroscopically homogeneous systems with high solubilization capacity of hydrophilic and hydrophobic compounds. The aim of this study was to evaluate the removal of high concentrations of lindane by the actinobacterium Streptomyces sp. M7 in aqueous and soil systems in the presence of stable microemulsions. Three stable microemulsions were successfully formed with Tween 80, 1-pentanol and three vegetable oils. In most cases, an increase in the cosurfactant/surfactant ratio in the microemulsions favored the solubilization of lindane, while an increase in the oil/surfactant ratio negatively affected the stability of the system. The microemulsion prepared with soybean oil allowed the solubilization of 66% of lindane added to the aqueous medium and 4.5 times more than the surfactant solution at the same concentration. This microemulsion increased the bioavailability of lindane in the aqueous medium and hence enhanced its removal by Streptomyces sp. M7 almost two times respect to the achieved with the surfactant solution. In loam soil system, the addition of the microemulsion allowed an 87% of lindane removal by Streptomyces sp. M7, increasing almost 50% the removal respect to the obtained without the addition of surfactant agents, although it did not present significant difference respect to the obtained with the surfactant solution. This is the first report on enhanced lindane removal by actinobacteria by using direct microemulsions as bioremediation tools.
林丹是一种有机氯农药，因其含氯和疏水的特性而在环境中持久存在，并可能导致严重的健康问题。微乳液是各向同性且宏观上均匀的体系，对亲水和疏水化合物具有高增溶能力。本研究的目的是评估在稳定微乳液存在的情况下，放线菌链霉菌属M7在水相和土壤体系中对高浓度林丹的去除情况。用吐温80、1 - 戊醇和三种植物油成功形成了三种稳定的微乳液。在大多数情况下，微乳液中助表面活性剂/表面活性剂比例的增加有利于林丹的增溶，而油/表面活性剂比例的增加对体系的稳定性有负面影响。用大豆油制备的微乳液能够增溶添加到水介质中的66%的林丹，且在相同浓度下比表面活性剂溶液多增溶4.5倍。这种微乳液提高了林丹在水介质中的生物可利用性，因此与表面活性剂溶液相比，链霉菌属M7对其去除率提高了近两倍。在壤土体系中，添加微乳液后链霉菌属M7对林丹的去除率达到87%，与不添加表面活性剂时相比，去除率提高了近50%，不过与表面活性剂溶液处理的结果相比没有显著差异。这是关于使用直接微乳液作为生物修复工具增强放线菌去除林丹的首次报道。
