Immobilized microbial nitrilase for production of glycolic acid

A 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).