Production of optically pure L-valine in fluidized and packed bed reactors with immobilized L-aminoacylase

A process to obtain L-valine has been developed using fluidized and packed bed reactors with L-aminoacylase (from hog kidney) immobilized by covalent binding, L-Valine production using the immobilized derivative of L-aminoacylase in fluidized and packed bed reactors was studied at three different substrate concentrations and two different how rates. Higher productions were obtained in the packed bed reactor in all cases. The different solubilities of L-valine and acetyl-D-valine in ethanol were used to purify L-amino acid from the reactor effluents, The amount of added ethanol did not influence the separation yields, although the purity of L-valine was strongly affected by this parameter. The last step involved was racemization of the unhydrolyzed acetyl-D-valine, which was then used as substrate in a new reaction cycle. (C) 1999 Society of Chemical Industry.