Optimization and production of probiotic and antimycotoxin yeast biomass using bioethanol industry waste via response surface methodology

Abstract

Saccharomyces cerevisiae RC016 presents probiotic and mycotoxin adsorbent properties for use as feed additive. The improvement of S. cerevisiae RC016 biomass production using an agro-industrial waste such as Dried Distillers'Grains and Solubles (DDGs) that pollute the environment can contribute to sustainable development of the process and reduce the costs of large-scale production. In order to avoid theobstruction of the fermentor?s stirring mechanism with solid particles a novel pre treatment of DDGs was conducted to concentrate carbon sources levels. The design of experiments were performed using four factor-three-level Box-Behnken design (carbon source concentration, nitrogen source concentration, yeast extract concentration and incubation time) coupled with response surface methodology to evaluate theinteraction between two factors in order to determine the optimum process conditions. A quadratic model was suggested for the predictionof biomass production. The F-value and p-value of the model indicated that it was statistically significant at 95 percent confidence interval. Inaddition, R2 value of the model indicated an acceptable accuracy. The results were validated at bioreactor level showing that the specific growthrate on the optimized medium (0.34h-1) increased 112.5% compared to the initial non-optimized medium (0.16h-1), the duplication time showeda decrease of 52.9%. Optimization enabled productivity (0.451gL-1h-1) nine times higher than the initial one (0.062gL-1h-1), thus 65% more biomass was obtained (5.20gL-1). The use of biomass DDGse derived from bioethanol production promotes the sustainable and green way of biomass production.