Removal of anthracene from model wastewater by immobilized peroxidase from Momordica charantia in batch process as well as in a continuous spiral-bed reactor

The aim of this study was to develop a system based on the use of immobilized peroxidase from bitter gourd (Momordica charantia) for the removal of polycyclic aromatic hydrocarbon, anthracene. In vitro removal of anthracene by soluble and calcium alginate–starch beads surface immobilized peroxidase was investigated in the presence of a redox mediator, guaiacol. The maximum oxidation of anthracene was observed in the presence of 0.70 mM H2O2 and 0.4 U mL−1 of the enzyme in sodium acetate buffer, pH 4.0 at 40 °C in 2.5 h. The oxidative degradation and polymerization of anthracene was increased more than two-fold in the presence of 0.1 mM guaiacol. The oxidation of anthracene was quite effective in batch process, 99% anthracene was removed in 7 h by immobilized enzyme. The spiral-bed reactor filled with immobilized enzyme retained more than 40% anthracene removal efficiency even after 1 month of its continuous operation. The absorption spectra of anthracene after treatment exhibited a marked difference in absorbance at respective wavelengths as compared to untreated compound. FT-IR analysis has shown a derivative of anthraquinone as a product of peroxidase catalyzed anthracene conversion. Allium cepa toxicity assay showed that the peroxidase catalyzed product of anthracene was less toxic as compared to parent compound.