fumaric acid to malic acid

At present, fumaric acid is usually produced by catalytic isomerization of maleic acid in aqueous solutions at reduced pH. Being oil based, requiring driver, and making great amounts of by-products and wastewater, typically the production of fumaric acid from green resources by a new “green” process is usually increasingly attractive. Inside an aqueous remedy, the reaction equilibrium continuous of the fumarase-mediated conversion of L-malic acid to fumaric acid is 1: 4. 2 (fumaric acid to L-malic acid). To shift the reaction equilibrium to fumaric acid, solvent engineering was carried out by varying hydrophilic solvents and their concentrations. Generally, natural solvents may denature fumarase. Therefore, fumarase from Thermus thermophilus was employed to overcome this problem. Ethylene glycol was found more suitable than other solvents. This fumarase was demonstrated to be more stable in 50% than in 70% ethylene glycol. Therefore, a preparation was carried out in 50% ethylene glycol. Under this condition, 54.7% conversion was observed using fumarase for transforming 1 mmol L-malic acid. After precipitation by adapting the pH, and washing to remove residual solvent and substrate, 27% total yield was obtained with 99% purity. The results demonstrated that the alternative green route to produce bio-based fumaric acid via L-malic acid is feasible and viable.