Biosynthesis, biotechnological production, and applications of glucosylglycerols

Abstract

Glucosylglycerols (GGs) are known as compatible solutes accumulated by some bacteria including cyanobacteria as well as higher plants for their adaptations to salt or desiccation stresses. Since being identified in Japanese sake, their physiological effects and potential applications on human health cares have been explored in the following 15 years. Several different synthesis methods have been successively developed for the production of GGs. However, the efficiency of GG synthesis, especially biological synthesis, is still low. With the recent advances in genome sequencing and synthetic biology tools, systematical screening of enzyme candidates and metabolic engineering approaches is necessary for improving GG synthesis efficiency. In this review, we will summarize GG structure information, protective effects on human skin and digestive system as well as industrial enzymes, together with their synthesis by chemical, enzymatic, and biological in vivo approaches in detail, and provide some prospects on improving GG production.

Production of the compatible solute α-d-glucosylglycerol by metabolically engineered Corynebacterium glutamicum

“…The here developed microbial production of the compatible solute αGG using a genetically engineered C. glutamicum strain offers an alternative to the hitherto described enzymatic syntheses of this compound [ 15 ] and αGG production with an genetically engineered strain of Synechocystis sp. PCC 6803 [ 26 ].…”

“…Currently many compatible solutes such as ectoine, hydroxyectoine, and trehalose are widely used as moisturizing agents in cosmetics [ 9 , 10 ], stabilizing agents for enzyme preparations, and/or as xeroprotectants for the storage of biomaterials and mammalian cells [ 11 – 13 ]. The compatible solute α- d -glucosylglycerol (αGG) has various beneficial functions and a large potential as a health food material, therapeutic agent, and for enzyme stabilization [ 14 , 15 ]. αGG serves as a compatible solute in various halotolerant cyanobacteria such as Synechocystis sp.…”

“…PCC 6803 strain produced extracellular αGG, however, it required first hyperosmotic stress for intracellular αGG synthesis via GGPS and GGPP and then a switch to hypoosmotic conditions to trigger αGG secretion via mechanosensitive channels in the culture broth [ 26 ]. Engineering of non-natively αGG synthesizing bacteria towards production of this compatible solute has hitherto not been described [ 15 ].…”

Identification of two two‐component signal transduction mutants with enhanced sucrose biosynthesis in Synechococcus elongatus PCC 7942

“…When stressed by sodium chloride (NaCl), cyanobacterial cells synthesize and accumulate high internal amounts of small organic compounds including sucrose, trehalose, glucosylglycerol, glucosylglycerate, glycine betaine, and homoserine betaine to protect cells against osmotic stress . Some of these small molecules are interesting products, since they can be used for food additives such as trehalose and sucrose, human nutrition such as sucrose, and moisturizing agents in skin care products such as trehalose and glucosylglycerol . In cyanobacteria, sucrose is synthesized from fructose‐6‐phosphate and UDP‐glucose via a two‐step pathway catalyzed by sucrose‐phosphate synthase (SPS) and sucrose‐phosphate phosphatase (SPP) .…”

Freshwater Cyanobacterium Synechococcus elongatus PCC 7942 Adapts to an Environment with Salt Stress via Ion-Induced Enzymatic Balance of Compatible Solutes

“…Recently, a novel compatible solute, homoserine betaine, was identified from the oceanic cyanobacterium Trichodesmium erythraeum (28). Among these compatible solutes, some have great potential for industrial or biotechnological applications, such as food additives, human nutrients, and moisturizing agents (29). Direct photosynthetic production of sucrose by cyanobacteria is also considered a potential strategy to provide abundant sugar feedstock for biorefineries (30).…”