α-glucosylglycerol: biological activities, emerging applications, and advances in sustainable biomanufacturing.

Glucosylglycerol (αGG, 2-O-α-D-glucopyranosyl-sn-glycerol) is a compatible solute produced by plants and diverse microorganisms under osmotic stress, consisting of glucose and glycerol linked via an α-1,2-glycosidic bond. Its high stability, low sweetness, and biocompatibility support growing interest in αGG as a functional ingredient for cosmetic and food applications and as a candidate for potential health-related uses, with preliminary reports of effects including skin hydration and barrier support, non-cariogenicity, and possible modulation of carbohydrate digestion. Despite these advantages, industrial deployment is still hindered by low productivity, by-product formation, and costly purification across existing routes, including extraction, chemical synthesis, microbial fermentation, and enzymatic production. This review integrates recent advances from microbiology and biotechnology, covering αGG-producing microbes and pathway insights, cell-factory engineering to improve precursor supply and redirect carbon flux, and regulation of transport and stress responses to enhance extracellular accumulation. Selective biocatalytic strategies for the synthesis of αGG based on various enzymes are also summarized, and the contributions of enzyme engineering, immobilization, whole-cell catalysis, and multi-enzyme cascade design to improved stability, selectivity, and space-time yield are highlighted. Finally, scale-up and process integration considerations are addressed, and actionable directions are proposed to enable sustainable and economically viable αGG manufacturing for food and health applications.