Patent ID: 7867748

Claim:
An isolated dehydrated enzyme catalyst having nitrilase activity with improved specific activity produced by a process comprising: (a) producing an enzyme catalyst having nitrilase activity by fermentation, said enzyme catalyst comprising a polypeptide having an amino acid sequence selected from the group consisting of SEQ ID NOs: 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 27, 29, 31, 33, 35, 37, 39, 41, 43, 45, 47, 49, 51, 53, 55, and 57; (b) pretreating said enzyme catalyst with glutaraldehyde; (c) optionally inactivating unreacted glutaraldehyde with bisulfite following glutaraldehyde pretreatment; (d) recovering the enzyme catalyst from (b) or (c) and immobilizing said enzyme catalyst in carrageenan; (e) cross-linking the resulting carrageenan-immobilized enzyme catalyst of (d) with glutaraldehyde and polyethylenimine; (f) producing a glutaraldehyde-pretreated immobilized and cross-linked enzyme catalyst, wherein said glutaraldehyde-pretreated immobilized and cross-linked enzyme catalyst has improved retention of initial specific activity during conversion of glycolonitrile to glycolic acid as compared to non-glutaraldehyde-pretreated immobilized and cross-linked enzyme catalysts under the same reaction conditions; and (g) dehydrating the cross-linked immobilized enzyme catalyst produced in step (f).