Comparison of differently modified Pseudomonas cepacia lipases in enantioselective preparation of a chiral alcohol for agrochemical use

Author： Xu Jian-He Zhou Rong Bornscheuer Uwe

Publisher： Informa Healthcare

ISSN： 1024-2422

Source： Biocatalysis and Biotransformation, Vol.23, Iss.6, 2005-11, pp. : 415-422

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Abstract

Three methods for enzyme modification/immobilization were compared to enhance the catalytic performance of a commercially available lipase, Lipase PS from Pseudomonas cepacia , in highly enantioselective transesterification of an agrochemically useful sec -alcohol, ( R , S )-HMPC [=( R , S )-4-hydroxy-3-methyl-2-(2′-propenyl)-2-cyclopenten-1-one], with vinyl acetate as both acyl donor and reaction medium. The stearic acid-coated lipase showed the highest catalytic activity, with a specific activity improved by 54 times over the native lipase. The microcrystal salt-supported lipase and celite-adsorbed lipase also displayed much better performance as compared with the native lipase. All the three modified lipase preparations showed a similar thermal stability to that of the native enzyme. The enantioselectivity ( E -value) was also quite satisfactory in all the cases ( E >100 at 30°C), though a trend of slight decline was also observed with the temperature increase in the range of 25–60°C. The optimum aqueous pH, from which the modified lipases were prepared, was 6.0–7.0. A low water activity ( a w ) of ca. 0.1 was favorable for all the three modified lipases. The stearic acid-coated lipase displayed prominent advantages in catalyzing the transesterification reaction at a very high ( R , S )-HMPC concentration up to 1.0M.