Bioremediation of soil contained with lubricant oil by different solutions of chemical surfactant and Pseudomonas aeruginosa LBI biosurfactant.

Abstract

The search for new chemicals in agriculture, cosmetics, food, pharmaceutical and environmental industries is increasingly higher. Because these products must be effective and environmentally compatible, compounds produced by microorganisms represent this alternative. Fungi, yeasts and bacteria are able to produce a variety of substances with great biotechnology industry application, such as biosurfactants. Despite biosurfactants advantages compared with synthetic surfactants, such as low toxicity, biodegradability and high stability, biotensoactives are not widely used because of their production cost. Nevertheless, there already are studies about the production of biosurfactants, but few reports that detail their environment behavior and its application in soil contaminated by hydrocarbons. Therefore, the present study aims the production and application of rhamnolipids (biosurfactants) produced by Pseudomonas aeruginosa LBI, potentially producing bacterium surfactants, in contaminated environment with lubricant oil. Also, it will be evaluated effects of adding these compounds in a commercial detergent composition, comparing with two commercial surfactants: synthetic biosurfactants. Rhamnolipid production will be from agro-industrial residue as substrate, thus contributing to cost reduction. Its application in soil contaminated with used lubricant oil will be assessed by: biodegradation assays (respirometry and colorimetry), toxicological tests before and after microbial activity and microorganisms diversity molecular analysis of the systems proposed. Therefore, this study will investigate the application of rhamnolipids produced by Pseudomonas aeruginosa LBI, contributing to new strategies development for bioremediation of environments contaminated by petroleum hydrocarbon and to possibility of using biosurfactants in a commercial detergent composition.