Conversion Of Fumaric Acid Research Articles

Study of silanized nanostructures with immobilized fumarase for production of L-malate.

The conversion of fumaric acid into L-malate by fumarase immobilized on silanized nanostructures was analyzed experimentally. The enzyme was bound to the silanized nanostructures. We carried out scanning electron microscopy (SEM), fourier transform infrared spectroscopy (FTIR) analysis, zeta size analysis and surface area calculation for the characterization of the nanostructures. The effect of initial enzyme concentration and pH on immobilization procedure were investigated and the change of Michaelis-Menten constants (Km and Vmax) with immobilization was examined. The change in the storage stability of the enzyme by immobilization was also investigated. The stability of the immobilized enzyme was very good. We observed that the fumarase was bound to silanized nanostructures [p(HEMA)-3-MTES] in much greater amounts. We have compared the activities of free fumarase and immobilized fumarase and we have observed a significant increase in the activity of the fumarase after immobilization for L-malate production. Moreover, we came to the conclusion that this activity can be better preserved for 30 days compared to free fumarase.

Study of an enzyme membrane reactor with immobilized fumarase for production of L-malic acid.

The conversion of fumaric acid into L-malic acid by fumarase immobilized in a membrane reactor was analyzed experimentally. The enzyme was entrapped in asymmetric capillary membranes made of polysulfone. The performance of the reactor was evaluated in terms of conversion degree, reaction rate, and stability. The influence of operating conditions, such as amount of immobilized enzyme, substrate concentration, residence time, and axial flow rate, were investigated. The kinetic parameters K(m), V(max), and k(+2) were also measured. The stability of the immobilized enzyme was very good, showing no activity decay during more than 2 weeks of continuous operation.

Production of L-aspartic acid from fumaric acid by Alcaligenes metalcaligenes CCEB 312.

Among 23 microbial strains, Alcaligenes metalcaligenes CCEB 312 was found to be most suitable for the conversion of fumaric acid to L-aspartic acid. In a growth medium containing 4% peptone, the strain produced as much as 50 g L-aspartic acid per litre.