Bioproduction of ethylenediamine-N,N'-disuccinic acid using immobilized fumarase-free EDDS lyase

Abstract Ethylenediamine-N,N\u0027-disuccinic acid (EDDS) is a promising chelating agent for the remediation of heavy metal-contaminated soil. In general, EDDS is produced through a chemical method. In this study, we report an efficient biotechnological approach for EDDS production using an immobilized enzyme. We expressed the EDDS lyase in E. coli and obtained 19.8 g/L of EDDS through a reaction catalyzed by crude enzymes, containing EDDS lyase and fumarase. After performing metal affinity chromatography-mediated purification, we thoroughly eliminated the fumarase activity, which could result in the unnecessary formation of malate. Then, the purified EDDS lyase was immobilized on a glutaraldehyde-activated amino carrier, and the immobilized enzyme was used in 11 batches (864.5 h). After optimization, 209.3 g/L EDDS was obtained in a 100 mL reaction system, resulting in 20.2 g of EDDS product with a purity of 99.8 % after isolation. The yields of reaction and isolation were 94.0 % and 91.8 %, respectively. In conclusion, this study describes a promising bioproduction process for industrial-level EDDS production.