Rhizopus oryzae Hydrolases from Solid-State Fermentation: A Gateway to Food Waste Valorization

Moulds of the Rhizopus oryzae species exhibit high biotechnological potential due to their significant metabolic activity, which is influenced by cultivation conditions. The study aimed to evaluate the ability of R. oryzae DSM 2199 to synthesize extracellular lipolytic and proteolytic enzymes in solid-state fermentation (SSF) using rapeseed cake as a substrate. The effectiveness of the SSF method in stimulating the synthesis of hydrolytic enzymes by R. oryzae was confirmed. The effect of an additional carbon and nitrogen source with three different dilution variants of the solid substrate on lipase and protease activity was analyzed. No significant correlation was found between enzyme activity and the applied diluents. The extracellular enzyme solution obtained from R. oryzae in SSF was lyophilized. The freeze-dried raw preparation exhibited high lipolytic activity (111.59 U/g) compared to its low proteolytic activity (0.013 U/g). Demonstrated hydrolytic activity made the biocatalyst useful for the hydrolysis and esterification reactions.