Production of glucosyl glycerol by immobilized sucrose phosphorylase: Options for enzyme fixation on a solid support and application in microscale flow format

2-O-(alpha-d-Glucopyranosyl)-sn-glycerol (alpha GG) is a natural osmolyte. alpha GG is produced industrially for application as an active cosmetic ingredient. The biocatalytic process involves a selective transglucosylation from sucrose to glycerol catalyzed by sucrose phosphorylase (SPase). Here we examined immobilization of SPase (from Leuconostoc mesenteroides) on solid support with the aim of enabling continuous production of alpha GG. By fusing SPase to the polycationic binding module Z(basic2) we demonstrated single-step noncovalent immobilization of the enzyme chimera to different porous supports offering an anionic surface. We showed that immobilization facilitated by Z(basic2) was similarly efficient as immobilization by multipoint covalent attachment on epoxy-activated supports in terms of production of alpha GG. Enzyme loadings of up to 90 mg enzyme g(-1) support were obtained and the immobilized SPase was about half as effective as the enzyme in solution. The high regio- and chemo-selectivity of soluble SPase in alpha GG synthesis was retained in the immobilized enzyme and product yields of >85% were obtained at titers of similar to 800 mM. The Z(basic2)-SPase immobilizates were fully recyclable: besides reuse of the enzyme activity, easy recovery of the solid support for fresh immobilizations was facilitated by the reversible nature of the enzyme attachment. Application of immobilized Z(basic2)-SPase for continuous production of alpha GG in a microstructured flow reactor was demonstrated. Space-time yields of 500 mmol alpha GG L-1 h(-1) were obtained at product titers of similar to 200 mM. The continuous microreactor was operated for 16 days and an operational half-life of about 10 days was determined. (C) 2017 Elsevier B.V. All rights reserved.