Decolorization of selected industrial synthetic dyes using laccase from an indigenous isolate strain SK1

Textile industrial wastewater is among the most polluting wastewater globally, necessitating efficient and sustainable treatment methods. Therefore, this study investigates the use of extracellular laccase, which is eco-friendly and cost-effective, particularly from an indigenous isolate coded as strain SK1, for bioremediation. The laccase production was optimized, leading to a 68% yield improvement when temperature, pH, agitation, and inoculum size were set at 35°C, pH 8, 150 rpm, and 5% v/v, respectively, using banana peel as the substrate. This optimization also reduced the incubation period by 67%. Remarkably, more than 65% decolorization was achieved with 100 mg/l concentrations of various dyes, including Congo Red, Alizarin Yellow, Methyl Orange, Methyl Red, Methylene Blue, Crystal Violet, and Malachite Green, within 60 minutes of incubation without mediators. Furthermore, the laccase application removed 99% of the dye from real batik wastewater, rendering the treated water safe for irrigation, as evidenced by a 98% germination rate of Vigna radiata. These findings underscore the effectiveness and practicality of laccase for textile wastewater treatment. Future research should focus on immobilizing laccase to enhance its biocatalytic performance, ensuring a robust and scalable bioremediation approach for industrial applications.