domingo, 28 de diciembre de 2008

Low temperature synthesis of 2-deoxyadenosine using immobilized psychrotrophic microorganisms

J. FERNANDEZ-LUCAS, L.A. CONDEZO, M.A. QUEZADA and J.V. SINISTERRA
Keywords
nucleoside 2-deoxyribosyl-transferases • synthesis of 2-deoxyribosyl nucleosides • psychrotrophic microorganisms • immobilized whole cells • calcium pectate • calcium alginate
Abstract
Selective biocatalyzed synthesis of 2-deoxyadenosine from 2-deoxypyrimidine nucleosides was carried out using free or immobilized whole cells. The reaction was performed at 57°C without secondary reactions. Two psychrotrophic microorganisms, Bacillus psychrosaccharolyticus and Psychrobacter immobilis, are described for the first time as active and specific strains for the synthesis of 2-deoxyadenosine. Adenosine deaminase activity was not detected. Whole cells were immobilized in different matrixes. Calcium alginate and calcium pectate gave the best biocatalysts. The synthesis of 2-deoxyadenosine follows an apparent first order kinetic expression. External mass transfer control was negligible as deduced from ks, NA, and values. Internal mass transfer was the rate controlling step according to T and values. Biotechnol. Bioeng. 2008;100: 213-222. © 2007 Wiley Periodicals, Inc.