Bio-Based Strategies for Producing Glycosaminoglycans and Their Oligosaccharides

Glycosaminoglycans (GAGs) and their oligosaccharides have attracted extensive attention because of their wide applications in cosmetics, health, and clinical treatment of, for example, thrombus, osteoarthritis, rheumatism, and cancer. Compared to conventional preparation approaches, bio-based strategies for producing GAGs and their oligosaccharides are more promising because they avoid cross-infection of human and animal diseases, use green production processes, and can precisely control the degree of sulfation and molecular weight. This review summarizes recently developed bio-based strategies for producing GAGs, highlighting in particular enzymatic, metabolic engineering, and synthetic biology strategies. Directions and prospects for near-future research are also outlined and discussed.