Microbe Selection and Optimizing Process Parameters for Degradation of Glucosinolates in Rapeseed Meal by Box-Behnken Design

The present study applied Aspergillus oryzae, Aspergillus niger, Penicillium purpurogenum, Trichoderma sp. MAB-2010b and Saccharomyces cerevisiae in solid state fermentation to degrade the glucosinolates in rapeseed meal. In addition, SDS-PAGE was used to determine the effect of hydrolysis of those five microbes on peptide size in rapeseed meal. The results indicated that the solid state fermentation with S. cerevisiae degraded the glucosinolates more than those with other microbes. The peptides were hydrolyzed by S. cerevisiae to a greater extent than others. Thus the following procedure was just focused on the solid state fermentation with S. cerevisiae. Box-Behnken design of response surface methodology was applied to optimize the substrate to water ratio, inoculum amount, and duration. The glucosinolate level in rapeseed meal was as the response. The optimal conditions derived from response surface methodology for S. cerevisiae fermentation were: 1.0 of substrate to water ratio, 1.5 mL (equal to 5%) of inoculum amount, and 48 h of duration. The minimum content of glucosinolates was 0.46 μmol/g dry matter. S. cerevisiae used in the present study thus exhibit the potential use in large scale solid state fermentation for increasing nutrition quality of rapeseed meal.