Recent advances in biocatalytic production of sugar acids

Sugar acids, as carbohydrate derivatives, are widely used in pharmaceuticals, food, and materials. Traditional chemical catalytic production methods can no longer meet the requirements for economic feasibility, safety, and atom economy, whereas biocatalysis has emerged as a promising alternative due to its environmental friendliness, safety, and sustainability. This review summarizes the recent advances in the biocatalytic production of three high-value sugar acids, namely glucaric acid, galactaric acid, and xylonic acid. Key strategies are critically discussed, including strain screening and engineering, enzyme engineering, enzyme immobilization, and fermentation process optimization. The advantages and disadvantages of different technological routes are compared in terms of yield, stability, and industrial applicability. Unlike existing reviews that primarily focus on chemical or biological production pathways, this review offers a new perspective by highlighting the challenges related to catalysts and reaction processes in sugar acid biosynthesis and the corresponding strategies to address them, aiming to provide insights for the development of sugar acid biosynthesis.