SELECTIVE PRECIPITATION OF L-PHENYLALANINE USING COPPER IONS AND ITS APPLICATION IN THE BIOCONVERSION OF PHENYLPYRUVIC ACID

This paper reports an alternative method for the recovery of L-phenylalanine from any mixture even at dilute concentrations. By selectively precipitating the L-phenylalanine as an insoluble copper complex, the product can be partially purfied and concentrated prior to further purification steps. Using immobilized cells of Pseudomonas fluorescens, L-phenylalanine produced from phenylpyruvate was precipitated in situ using copper acetate and the reaction continued by supplying fresh substrate. A recycle packed bed reactor was set up with the L-phenylalanine (product) in the reactor effluent continuously precipitated with copper ions. After 102 h operation, 103. 7 g of partially pure L-phenylalanine was recovered from the pooled precipitates. The merits of this efficient recovery method are discussed.