Production of ß-galactosidase by Trichoderma sp. through solid-state fermentation targeting the recovery of galactooligosaccharides from whey cheese.

AIMS: Optimization of ß-galactosidase production by Trichoderma sp. under solid-state fermentation using wheat bran as solid substrate through an experimental design and its application targeting the recovery of galactooligosaccharides (GOS) from whey cheese. METHODS AND RESULTS: The ß-galactosidase production by Trichoderma sp. increased 2·3-fold (2·67 U g-1 of substrate) culturing the fungus at 30°C for 187 h, at an inoculum of 105 spores per ml, and a 1 : 1·65 (w/v) ratio of wheat bran to tap water. The best enzyme activity was obtained at 55°C and pH 4·5. The catalytic activity was maintained for up to 180 min incubating at 35-45°C, and above 50% at acidic or alkaline pH for up to 24 h. It also presented resistance to chemical compounds. ß-galactosidase catalysed the hydrolysis of the lactose and the transgalactosylation reaction leading to the production of GOS. CONCLUSION: Trichoderma sp. produced ß-galactosidase with transgalactosylation activity that may be used to recover GOS, products with high added value, from whey cheese. SIGNIFICANCE AND IMPACT OF THE STUDY: ß-galactosidases are used in different industrial sectors. Therefore, the Trichoderma ß-galactosidase is a promising alternative for the production of GOS as prebiotic from the dairy effluents, contributing to the reduction in the environmental impact.