PRODUCTION OF L-PHENYLACETYLCARBINOL BY FERMENTATION

In pharmaceutical industry, L-phenylacetylcarbinol (L-PAC) is used as an intermediate for the production of L-ephedrine hydrochloride--a wel l known bronchodilator. Certain yeast strains are known to transform b enzaldehyde to produce L-PAC with the help of a specific enzyme pyruva te decarboxylase (PDC) and pyruvate. Simultaneously another by-product , benzyl alcohol is also produced by another enzyme alcohol dehydrogen ase (ADH). Strains belonging to the genera Saccharomyces and Candida h ave been found to be more efficient L-PAC producers as comparison to o ther yeasts. The formation of L-PAC is determined by the growth and bi otransformation conditions. In the presence of benzaldehyde, cell grow th is adversely affected and L-PAC production is low. Harvested whole cells immobilized in different carriers have shown tolerance for highe r benzaldehyde doses and increased L-PAC yield has been obtained with semicontinuous mode of benzaldehyde biotransformation. Strain improvem ent also has effectively enhanced the yield of L-PAC. Studies with iso lated PDC enzyme have shown significant potential for improving the L- PAC yield.