Production of galactooligosaccharide by Scopulariopis sp.

The galactooligosaccharides (GOS), a group of oligosaccharides, are not digerible carbohydrates (NDOs) and are resistant to hydrolysis by intestine digestive enzymes with similar dietary fiber physiological effect. The benefits of galactooligosaccharides ingestion arise from a population of bifidobacteria in the colon that suppress the activity of putrefactive bacteria and reduce the formation of toxic fermentation products. Scopulariopsis strains showed good productivity of P-galactosidase when grown in a semi-solid fermentation medium. The aim of this work was to extract the P-galactosidase from Scopulariopsis sp. and to evaluate the temperature conditions, reaction time, lactose, and enzyme concentration to improve the GOS production. Temperatures of 35, 45, and 60 degrees C, reaction time at 12, 24 and 48 hours, enzyme concentrations from 0.5 to 10 UmL(-1), and 10, 25, and 40%(w/v) of lactose solution (0,1 M of acetate buffer, pH 5.0) were analyzed. The optimum conditions were 40% (w/v), at 45 degrees C, 10 U.mL(-1) of enzyme and the optimum time was 12 hours of reaction. Under these conditions, the enzyme converted 20% of lactose into oligosaccharide (80.8 mg.mL(-1) de 4'galactosyl-lactose).