A Novel Xylan-Polyvinyl Alcohol Hydrogel Bead with Laccase Entrapment for Decolorization of Reactive Black 5

• Main Authors: Wichnaee Bankeeree, Sehanat Prasongsuk, Tsuyoshi Imai, Pongtharin Lotrakul, Hunsa Punnapayak
• Format: Article
• Language: English
• Published: North Carolina State University 2016-07-01
• Series: BioResources
• Subjects: Hydrogel; Reactive Black 5; Immobilization; Trametes versicolor; Alkaline tolerant
• Online Access: http://ojs.cnr.ncsu.edu/index.php/BioRes/article/view/BioRes_11_3_6984_Bankeeree_Novel_Xylan_Polyvinyl_Alcohol_Hydrogel

In an attempt to find a more efficient technique for biodegradation of the recalcitrant Reactive Black 5 (RB-5) dye, a composite xylan-polyvinyl alcohol (xylan-PVOH) hydrogel was used to immobilize laccase from the white-rot fungus Trametes versicolor. Xylan was prepared from the black liquor of pulp and paper effluent, and it was esterified with citric acid prior to cross-linking with polyvinyl alcohol (PVOH). The optimum composition for the immobilized laccase bead formation consisted of 4% (w/v) modified xylan, 10% (w/v) PVOH, and 15 U.mL-1 crude laccase. The maximum decolorization of RB-5 (98.45  1.96 %) was obtained within the first cycle (6 h) at 40 °C. In the eighth cycle, the reused beads were able to decolorize 55.35  2.46 % of the RB-5. Moreover, the xylan-PVOH beads extended the optimum pH range of laccase activity from 6 to 10 and tolerated a temperature up to 10 °C higher than that of the free enzyme. These results suggest that the xylan-PVOH bead has great potential as the polymer matrix for enzyme immobilization, which has applications in wastewater treatment.