Recent advances in polygalacturonase: Industrial applications and challenges

This review focuses on the applications of polygalacturonase (PG), one of the most commercially produced enzymes on the biocatalyst market, in the food, beverage, feed, textile, and paper industries. Most PGs are acidic mesophilic enzymes, as shown by a summary of their biochemical properties. However, the acidic PGs discovered to date are insufficiently effective for industrial applications. The sequence and structural characteristics of thermophilic PGs are analyzed based on the results of extensive discussions regarding the catalytic mechanism and structural characteristics of PGs with shared right-handed parallel β-helical structures. In addition, the molecular modification methods for obtaining thermostable PGs are systematically presented. Notably, the demand for alkaline heat-resistant PGs has increased significantly concurrent with the biomanufacturing industry development. Therefore, this review also provides a theoretical guideline for mining heat-resistant PG gene resources and modifying PG thermostability.