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Optimizing lipase activity, enantioselectivity, and stability with medium engineering and immobilization for β‐blocker synthesis
Author(s) -
Mohapatra Satish C.,
Hsu James T.
Publication year - 1999
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/(sici)1097-0290(19990720)64:2<213::aid-bit10>3.0.co;2-u
Subject(s) - chemistry , acetone , lipase , enantioselective synthesis , hydrolysis , polyethylene glycol , dimethylformamide , solvent , tetrahydrofuran , methanol , triacylglycerol lipase , organic chemistry , candida antarctica , catalysis , enzyme
Lipase from Pseudomonas cepacia showed poor activity and moderate enantioselectivity ( E ) in pure aqueous systems for hydrolysis of a racemic mixture (±)‐1‐chloro‐2‐acetoxy‐3‐(1‐naphthyloxy)‐propane, which is a potential intermediate for β‐blocker synthesis. However, addition of polar organic solvents to the reaction can change both the activity and the enantioselectivity for this chiral reaction significantly. It was observed, in general, that the activity increases and the enantioselectivity decreases with the increase in the polarity of the organic solvent added to the medium. Among the six solvents chosen (i.e., dimethylsulfoxide [DMSO], 1,4‐dioxane, dimethylformamide [DMF], acetone, 1‐propanol, and tetrahydrofuran [THF]), maximum activity and minimum enantioselectivity was obtained with DMSO, whereas minimum activity and maximum enantioselectivity was obtained with THF as the cosolvents. In the subsequent studies, native or polyethylene glycol (PEG)‐modified lipase was immobilized by entrapping in Caalginate gel beads. In a fixed‐bed continuous reactor containing these catalyst beads, the enzyme was found to be at least three times more enantioselective than the native form in a batch reactor. This fixed‐bed reactor with the beads could be operated with high concentration of acetone (33% v/v) for about 1 month without a significant loss of enzyme activity and enantioselectivity. © 1999 John Wiley & Sons, Inc. Biotechnol Bioeng 64: 213–220, 1999.