Application of calcium carbonate nanoparticles and microwave irradiation in submerged fermentation production and recovery of fumaric acid: a novel approach

Abstract

The aim of the present study was to explore the possible application of calcium carbonate nanoparticles (CCNPs) and microwave irradiation (MWI) in fumaric acid (FA) production and recovery, respectively. The fungal strain Rhizopus oryzae 1526 was employed as the biocatalyst for FA production. A glucose-basic salt medium was used as the fermentation medium. Scanning electron microscopy (SEM) analysis of CCNPs displayed the spherical shapes, while zetasizer measurements showed the CCNPs to be around 190 ± 20 nm in size. FTIR analysis of CCNPs confirmed the chemical composition. BET analysis confirmed higher specific surface areas of CCNPs (11.95 ± 0.03 m² g⁻¹) compared to calcium carbonate microparticles (CCMPs) (3.51 ± 0.02 m² g⁻¹). FA neutralization timing for CCNPs was much lower than CCMPs (190 and 350 seconds, respectively). CCNPs enhanced the volumetric productivity of FA from 0.47 g L⁻¹ h⁻¹ to 0.74 g L⁻¹ h⁻¹. At 20, 40 and 60 g L⁻¹ concentrations and at 25 °C, viscosities of the CCNPs were found to be lower than respective CCMPs. Moreover, the CCNPs did not exhibit any toxicity towards the fungus. FA production obtained with CC micro and CCNPs were 67.34 ± 2 g L⁻¹ and 66.92 ± 2.7 g L⁻¹, respectively. Under MWI heating, 10 ± 1 min was found to be sufficient for recovery of FA and this was much lower than conventional heating timing of 28 ± 1 min.