Biosurfactant production in low-cost medium formulated with sea water

Abstract

The development of biodegradable and low toxicity surfactants, as the biosurfactants obtained by microbiological synthesis, is becoming a strategy in obtaining more compatible components with the environment. In this work, the production of biosurfactants by Candida sphaerica was studied using a factorial design. The influence of the following culture medium components, named vegetal oil refinery residue, corn steep liquor and sea water on the surface tension reduction was evaluated. The best surface tension (27 mN m-1) was found in the central point of the experimental design (medium formulated with 4% refinery residue, 4% corn steep liquor and 50% of sea water). The growth kinetics demonstrated that the stationary phase was reached in the first 48 hours of cultivation. Higher emulsification indexes had been observed with motor oil, corn oil and cotton oil. Stability tests of the emulsions submitted to different temperatures and in the presence of NaCl revealed few variations under the specific environmental conditions studied, showing great potential of the surfactant to be used for environmental and industrial applications. The promising results obtained indicate the viability of powerful biosurfactants produced from low-cost medium based on sea water.