Evaluation of a new strategy in the elaboration of culture media to produce surfactin from hemicellulosic corncob liquor

Abstract

The biosurfactant production is characterized by high costs with substrates, which does not make them sufficiently competitive against synthetic surfactants. The insertion of alternative sources of low cost, especially agro-industrial residue, is an excellent alternative to make this competitiveness viable. An alkaline pretreatment was used to extract the hemicellulose from corncob in order to enhance its C5 fraction, common to vegetable biomasses. The hemicellulosic corncob liquor was used with glucose and mineral salt solution as carbon and nutrients sources in a fermentation process for the growth of Bacillus subtilis. It was performed a 23 full factorial design to determine the best conditions for the surfactin production in relation to the following response variables: surface tension reduction rate (STRR) and emulsification index (EI24), from which were obtained two optimized bioproducts under specific conditions. The optimized biosurfactants found to be effected presenting a critical micelle concentration of 100 mg.L−1 and a maximum bioremediation potential of 85.18%, as well as maximum values of 57.38% and 65.30% for STRR and EI24 variables, respectively. Overall results pointed for a successful commercial application for the surfactin produced. Keywords: Biosurfactant, Design of experiments, Lignocellulosic residue, Hemicellulosic corncob liquor, Bioremediation