Efficient preparation of (R)-a-monobenzoyl glycerol by lipase catalyzed asymmetric esterification: optimization and operation in packed bed reactor. Biotechnol Bioeng 2001;73:493–9
Abstract: Optically active (R)-a-monobenzoyl glycerol (MBG) was synthesized by Candida antarctica lipase B (CHIRAZYMET L-2) catalyzed asymmetric esterification of glycerol with benzoic anhydride in organic solvents. Vari-ous conditions, such as the type and composition of the organic solvent, water...
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| Language: | English |
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| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.528.8926 http://www.pu-toyama.ac.jp/BR/asano/pdf/MBG3.pdf |
| Summary: | Abstract: Optically active (R)-a-monobenzoyl glycerol (MBG) was synthesized by Candida antarctica lipase B (CHIRAZYMET L-2) catalyzed asymmetric esterification of glycerol with benzoic anhydride in organic solvents. Vari-ous conditions, such as the type and composition of the organic solvent, water content of the system, reaction temperature, and concentrations of the substrates were systematically examined and optimized in screw-capped test tubes with respect to both the reaction rate and the enzyme selectivity. 1,4-Dioxane was found to be the best solvent and no additional water was needed for the sys-tem. The optimum temperature was around 30°C, while the most suitable substrate concentrations were 100 mM each for glycerol and benzoic anhydride, respectively. However, when excessive anhydride (e.g., 200 mM) was used, the produced MBG could be further transformed into 1,3-dibenzoyl glycerol (DBG) by the same enzyme with a priority to (S)-MBG, resulting in a significant im-provement of the product optical purity from ca. 50–70% e.e. Under optimal conditions (100 mM glycerol, 100–200 mM benzoic anhydride, dioxane, 25–30°C), the enzymatic synthesis of (R)-MBG was successfully operated in a packed-bed reactor for about 1 week, with an average productivity of 0.79 g MBG/day/g biocatalyst in the case of continuous operation and 0.94 g MBG/day/g biocata-lyst in the case of semicontinuous operation. After refine-ment and preferential crystallization of the crude prod-uct, (R)-MBG could be obtained in an almost optically |
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