Immobilization of a peroxidase from Moringa oleifera Lam. roots (MoPOX) on chitosan beads enhanced the decolorization of textile dyes

Abstract The textile industry is essential, but it is also responsible for causing environmental problems, particularly the discharge of dyes. In this context, this study aimed to immobilize a previously purified peroxidase, called MoPOX, on glutaraldehyde-activated chitosan beads in order to improve the potential for textile dye decolorization. The chitosan beads were activated with 8% glutaraldehyde for 1 h, and the immobilization was performed at 30 °C, pH 5.2 for 4 h. Scanning Electron Microscopy (SEM) analyses were used to observe the differences in the chitosan beads after immobilization. The optimum temperature dropped from 70 °C to 30 °C after immobilization, but immobilized MoPOX demonstrated excellent heat stability. The optimum pH remained 5.2, while the apparent kinetic constant value (Km) of immobilized MoPOX (14.67 mM) was lower in comparison to free MoPOX (46.8 mM). The immobilized enzyme showed improved activity after long storage times, and it could retain 40 % of its original activity even after 5 cycles. The potential for decolorization of different textile dyes was considerably enhanced after immobilization, reaching more than 80 %. Also, MoPOX showed no toxicity towards Artemia salina. Overall, the findings point to the promising potential of using immobilized MoPOX as a biocatalyst in a variety of biotechnological applications.