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

Aims: Optimization of β-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 β-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. β-galactosidase catalysed the hydrolysis of the lactose and the transgalactosylation reaction leading to the production of GOS. Conclusion: Trichoderma sp. produced β-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: β-galactosidases are used in different industrial sectors. Therefore, the Trichoderma β-galactosidase is a promising alternative for the production of GOS as prebiotic from the dairy effluents, contributing to the reduction in the environmental impact.