Improvements in immobilized microbial nitrilase for the production of glycolic acid

摘要

A process for producing an enzymatic catalyst pretreated with immobilized and crosslinked glutaraldehyde, said process comprising: (a) producing by fermentation an enzyme catalyst having nitrilase activity; (b) pretreating said enzyme catalyst with glutaraldehyde; (c) optionally inactivate unreacted glutaraldehyde with bisulfite after glutaraldehyde pretreatment; (d) recovering the enzyme catalyst from (b) or (c) and immobilizing said enzyme catalyst in carrageenan; (e) crosslinking the enzyme catalyst immobilized in carrageenan resulting from (d) with glutaraldehyde and polyethyleneimine; and (f) producing an enzymatic catalyst pretreated with glutaraldehyde, immobilized and crosslinked, wherein said enzymatic catalyst pretreated with immobilized and crosslinked glutaraldehyde has a better retention of the initial specific activity during the conversion of glycolonitrile to glycolic acid compared to non-enzymatic catalysts. pretreated with glutaraldehyde, immobilized and crosslinked under the same reaction conditions; wherein said enzyme catalyst comprises a polypeptide having an amino acid sequence selected from the group consisting of SEQ ID NO: 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.