The Performance of Nanofiltration Membrane in Concentrating Folic Acid from Fermented Mungbean (Phaseolus radiatus L.) by Rhizopus oligosporus Strain-C1 and Rhizopus sp. for Recovery Efficiency of Natural Folic Acid

Abstract

This research was conducted to evaluate the performance of the nanofiltration (NF) membrane in concentrating permeate obtained from the ultrafiltration (UF) membrane of fermented mung bean. The procedure was performed to determine both the best flux and efficiency of recovering folic acid from the multi-filtration process. Feed A and Feed B were used as ultrafiltered permeate of fermented mung bean (Phaseolus radiatus L.) obtained using Rhizopus oligosporus strain-C1 and Rhizopus sp., respectively. These feeds were subjected to the NF membrane installed in crossflow filtration (CFF) module system at room temperature, flow rate ~7.5 L/min. and transmembrane pressure (TMP) of 10 bar for 0, 15, 30, 45, 60, 75 and 90 minutes. The results showed that based on the optimum flux, the best performance of the NF membrane for Feed A and B was achieved at 15 and 15 min, with permeate flux of 32.22 and 20.44 L/m2.h., respectively. Retentate A and B contained folic acid concentrations of 308.51 and 297.53 μg/mL, as well as total solids of 1.39% and 2.20%. Meanwhile, permeate A and B yielded folic acid concentrations of 106.88 and 63.77 μg/mL, with total solids of 0.22 and 0.32%. Under the NF process conditions, retentate A and B showed observed rejection (Robs) rates of folic acid at 65.35 and 78.56%, as well as total solids of 84.34 and 85.36%, respectively. There was also a 9.75 and 3.10% increase in folic acid with a 4.18% and 17.31% rise in total solids compared to the initial condition at 0 minutes. Molecular weight analysis of folic acid in permeate A and B after 15 min. and 15 min. of processing were dominated by monomer with a MW of 442.17 Da. Meanwhile, mass spectra of feed B for a processing time of 15 min. were dominated by monomers with MW of 442.19 and 442.47 Da, both with a relative intensity of 100%.