One-step elimination of l-cysteine desulfhydrase from crude enzyme extracts of Pseudomonas sp. TS1138 using an immunomagnetic affinity matrix improves the enzymatic production of l-cysteine

In this study, a high efficiency immunomagnetic affinity matrix was developed to eliminate l-cysteine desulfhydrase (CD), which decomposes l-cysteine, in crude enzyme extracts from Pseudomonas sp. TS1138. After cloning and expression in Escherichia coli, recombinant CD was purified to raise polyclonal antibodies from mice. The anti-CD antibody was cross-linked to staphylococcal protein A-magnetic cellulose microspheres (MCMS) with dimethyl pimelimidate (DMP). The natural CD was eliminated from the crude enzyme extracts by treatment with the cross-linked antibody-protein A-MCMS, resulting in a high level of l-cysteine production. The conversion rate of dl-2-amino-Δ2-thiazoline-4-carboxylic acid (dl-ATC) to l-cysteine increased significantly from 61.9 to 96.2%. The cross-linked antibody-protein A-MCMS showed its durability after repetitive use, maintaining a constant binding capacity for CD during five cycles. This study may lead to a convenient and cost-efficient method to produce l-cysteine by enzymatic conversions.