Environmentally benign synthesis of natural glycosides using apple seed meal as green and robust biocatalyst.
Salidroside is a natural glycoside with pharmacological activities of resisting anoxia, microwave radiation and fatigue, improving oxygen lack, and postponing ageing. In this work, salidroside and other natural glucosides such as cinnamyl O-beta-d-glucopyranoside and 4-methoxybenzyl O-beta-d-glucopyranoside were efficiently synthesized via an environmentally benign and energy economic process. In the synthetic process, apple seed, easily available from discards of fruit processing factories, was employed as a natural and green catalyst. Moreover, all of the catalyst, solvent and excessive substrate was reused or recycled. The biocatalytic reaction was carried out in a clean and less toxic medium of aqueous tert-butanol and the glucoside produced was selectively removed from reaction mixture by alumina column adsorption, making excessive substrate (aglycon) recyclable for a repeated use in the next batch of reaction. For improvement of the biocatalyst stability, apple seed meal was further cross-linked by glutaraldehyde, yielding a net-like porous structure within which the dissociating proteins were immobilized, resulting in improved permeability of the biocatalyst. After the simple cross-linking treatment, the half-life of apple seed catalyst was significantly improved from 29 days to 51 days. The productivity of the bioreactor in the case of salidroside can reach ca. 1.9 gl(-1)d(-1), affording the product in up to 99.3% purity after refinement.
Yu
Hui-Lei
HL
Laboratory of Biocatalysis and Bioprocessing, State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, PR China.
Xu
Jian-He
JH
Lu
Wen-Ya
WY
Lin
Guo-Qiang
GQ
D000537:Aluminum Oxide / Q000737:chemistry; D002384:Catalysis; D002851:Chromatography, High Pressure Liquid; D005959:Glucosidases / Q000378:metabolism; D005960:Glucosides / Q000737:chemistry; D006027:Glycosides / Q000096:biosynthesis / Q000138:chemical synthesis / Q000737:chemistry*; D027845:Malus / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D015394:Molecular Structure; D010636:Phenols / Q000737:chemistry; D012639:Seeds / Q000737:chemistry* / Q000378:metabolism / Q000648:ultrastructure
D005960:Glucosides; D006027:Glycosides; D010636:Phenols; D005959:Glucosidases; D000537:Aluminum Oxide; C009172:rhodioloside