Obtenção, purificação e caracterização de biosurfactante obtido por Bacillus subtilis ATCC 9372

Abstract

Surfactants are substances that have amphiphilic character in molecular structure to possess lipophilic and hydrophilic portions thus have the ability to incorporate at the interface of an insoluble mixture reduces the surface tension between them, and promoting the formation of an emulsion. However due to the extensive use of surfactants there has been a need to develop new production methods and the use of natural and renewable sources, featuring obtaining the biosurfactants. The biosurfactants may be obtained through a specific metabolic pathway of microorganisms. The use of these has been expanded, but the production cost of biosurfactants is still high when compared to surfactants. The present study aimed at obtaining, purification and characterization of biosurfactant produced by Bacillus subtilis. Thus the substrate, aqueous molasses, was hydrolyzed enzymatically and clarified, its pH was adjusted to 6.8 and held supplementation thereof; and then the medium was sterilized and then inoculated with Bacillus subtilis. The fermentation took place in a batch bioreactor 7L bench under agitation of 160 rpm at 36°C for 144 hours. To monitor the fermentation process were performed reducing sugar analysis (AR), pH, temperature, biomass and amount of biosurfactant, therefore, the biosurfactant was recovered and purified from the fermentation medium using the bubbling technique, followed by centrifugation, precipitation with solvent and dried in stove until constant weight. At the end of the process the biosurfactant obtained was characterized by FTIR, and emulsifying activity. The results demonstrate that the process parameters used, as well as molasses as culture medium was capable of providing a typical fermentation, with a possible technical feasibility. The product formed with the methanol purification showed higher emulsifying power. The FTIR showed only evidence of groups of surfactin, requiring further analysis to affirm the finished compost.