Utilization of soybean vinasse for α-galactosidase production

The enzyme α-galactosidase was produced by submerged fermentation using as substrate the soybean vinasse, a residue of the alcoholic fermentation of soybean molasses. Soybean molasses is a by-product of the protein-concentrate soybean meal production. The strain Lactobacillus agilis LPB 56 was selected among nine for presenting the highest enzymatic activity. The C:N relation in the vinasse-based inoculum medium was optimized and adjusted in 6 with yeast extract. The effects of soluble solids concentration in the fermentation medium, C:N relation and size of inoculum were investigated. Results demonstrated that the medium concentration of 30% soluble solids, with a C:N relation of 9, and size of inoculum of 25% (v/v) were the best conditions for α-galactosidase production. The highest enzyme activity (11.07 U/mL) was achieved after 144 h of fermentation.