Production of optically pure L-valine in fluidized and packed bed reactorswith 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-aminoacy lase in fluidized and packed bed reactors was studied at three different su bstrate concentrations and two different how rates. Higher productions were obtained in the packed bed reactor in all cases. The different solubilitie s of L-valine and acetyl-D-valine in ethanol were used to purify L-amino ac id from the reactor effluents, The amount of added ethanol did not influenc e the separation yields, although the purity of L-valine was strongly affec ted by this parameter. The last step involved was racemization of the unhyd rolyzed acetyl-D-valine, which was then used as substrate in a new reaction cycle. (C) 1999 Society of Chemical Industry.