Screening of DERA activity in bacteria: Whole cell biocatalyzed synthesis of 2-deoxyriboses-5-phosphate

ANA VALINO; MARTÍN PALAZZOLO; ELIZABETH LEWKOWICZ; ADOLFO IRIBARREN

Berna

Simposio; 9th International Symposium on Biocatalysis and Biotransformation; 2009

The synthesis of 2-deoxyribose-5-phosphate (DR5P) is a key step in the preparation of nucleosides. Both the chemical synthesis of deoxyriboses and the following production of deoxynucleosides require several and complex steps including those of protection and deprotection. For this reason, the study of simpler, cleaner and economic alternative paths becomes highly interesting. Aldolases catalyze the stereoselective C-C bond formation through a condensation reaction that involves carbonylic compounds. Among them, 2-deoxyribose-5-phosphate aldolase (DERA) is the only aldolase that accepts two aldehydic substrates for DR5P production: D-glyceraldehyde-3-phosphate (G3P) and acetaldehyde. With the aim of selecting microorganisms containing DERA activity, our bacteria collection was screened for finding those ones capable to metabolize 2-deoxyribose and to tolerate high acetaldehyde concentration. Ten microorganisms belonging to the Bacillus, Xanthomona, Streptomyces and Erwinia genera were identified. These bacteria were tested for the DR5P production through the aldolic condensation described above from different starting material for G3P in situ production. Consequently, unreported C74 strain from the Erwinia genus demonstrated to be an efficient biocatalyst for DR5P biosynthesis through a simple and clean process. Finally, the proposed biotransformation was used for the preparation of 2-b-substituted-2-deoxyriboses-5-phosphate from different aldehydic donors.