Microbial Tannase for Food Bioprocessing: Enzyme Production, Enzyme Engineering, and Tannin Valorization

Microbial tannase (TAN; tannin acyl hydrolase, EC 3.1.1.20) is an important food-processing enzyme because it hydrolyzes the ester and depside linkages in hydrolyzable tannins and galloyl-containing compounds. This review discusses how advances in microbial production, enzyme engineering, and immobilization have expanded its potential for food processing and tannin-rich residue valorization. Reported TAN engineering strategies have improved acid tolerance and thermostability, whereas immobilization has facilitated enzyme recovery and repeated use. Food and beverage applications include haze and astringency reduction, modification of gallated catechins, gallic acid (GA) enrichment, and improved phenolic bioaccessibility. Tannin-rich agro-industrial residues provide feedstocks for enzyme production and biotransformation into value-added phenolic compounds. However, industrial translation remains limited by insufficient validation in complex food matrices and scarce evidence of long-term operational performance and economic feasibility. Therefore, the requirements for matrix-specific evaluation, reproducible enzyme production, validated recovery and reuse, and appropriate food-safety and economic assessment are also discussed. Overall, integrating enzyme development with realistic processing requirements is essential for establishing reliable TAN applications in the food and beverage industries.