Enhanced Production of a Bacterial Surfactant on Statistical Screening of Operational Parameters

Abstract

Biosurfactants have gained attention because they exhibit some advantages such as biodegradability, low toxicity, ecological acceptability and ability to be produced from renewable and cheaper substrates. However, the high cost of production is the limiting factor for widespread industrial applications. Thus, optimization of operational parameters for biosurfactant production by P. cepacia CCT6659 grown in a low-cost medium formulated with industrial wastes was carried out using response-surface methodology. The application of a central composite rotatable design (CCRD) led to the identification of agitation speed, time and inoculum size as significant variables affecting the fermentation process. The optimal levels of the aforementioned variables were 250 rpm agitation speed, 60h of cultivation time and 1.5% inoculum size. The experimental verifications substantiated the model predictions by showing a maximum relative surface tension reduction of 27 mN/m, which was found to be equivalent to about 8.0 g/l isolated biosurfactant as estimated gravimetrically, thereby resulting in an improved production