Enhancing biodecolorization of Malachite Green by Flavobacterium sp. through monothetic analysis

Malachite Green (MG) is a prevalent dye in the textile industry, known for its harmful environmental impacts. Addressing the urgent need for environmentally friendly and cost-effective methods to remove MG from wastewater, this study investigated the efficacy of Flavobacterium sp., isolated from Malaysian batik wastewater, in decolorizing MG. Under shaking conditions at 160 rpm, Flavobacterium sp. exhibited a notable decolorization efficiency, with 91 % removal of MG after a 3-day incubation time, surpassing the static mode efficiency of 39 %. Further optimization using a one-factor-at-a-time (OFAT) methodology at 37 °C, pH 10, 6 % (v/v) inoculum, banana peel as the carbon source and 250 mg/L MG resulted in a remarkable enhancement, achieving 95 % decolorization within a reduced incubation time of 12 h. Moreover, repeated addition of 250 mg/L MG showed consistent and complete decolorization after 6 h by Flavobacterium sp. for four successive cycles, suggesting its economic viability for treating actual Malaysian batik wastewater. Ultraviolet–visible (UV) analysis confirmed the biodegradation of MG, evidenced by the disappearance of characteristic peaks at 618 nm and the appearance of new peaks, indicating the formation of metabolites. Flavobacterium sp. reduced pH, temperature, color, TDS, TSS, BOD and COD in batik wastewater, showing 99 % color removal efficiency. This research highlights its potential as an eco-friendly, cost-effective treatment for batik wastewater. The capacity of Flavobacterium sp. to decolorize MG in an immobilized state will be the subject of future research endeavors, aimed at elucidating the adaptability and usefulness of the biocatalyst. • This paper reports on the competence of the Malaysian Flavobacterium sp. for the decolorization of Malachite Green. • Monothetic analysis reduced the decolorization time of Malachite Green by 83 %. • Flavobacterium sp. decolorizes Malachite Green at high pH, making it ideal for textile wastewater treatment. • The utilization of fruit waste as a carbon source supports enhanced decolorization and thus promotes sustainability.