Bioremediation of Triphenylmethane and Sulfonated Azo Dyes Using an Indigenous Strain of Trichoderma Asperellum: Mechanisms and Efficacy Assessment

Abstract

This study aimed to isolate a native fungal strain that was potent enough to curb the toxicity of azo dyes in textile effluent drain sludge. The native fungus, which has the potential to degrade several azo dyes under ‘non-sterile’ conditions, was isolated and identified as Trichoderma asperellum (TA). It was observed that the isolated strain was capable of decolorizing up to 71.42 %, 60.19 %, and 89.65 % of azo dyes (methyl orange, malachite green, and crystal violet, respectively) within a span of 14 days with an extensive range of temperatures (15°C-40°C) and pH (5-8) before optimization. The targeted dyes at concentrations of 100 mg/L, 200 mg/L, 300 mg/L, 400 mg/L, and 500 mg/L were decolorized after optimization. The maximum decolorization of methyl orange (MO), malachite green (MG), and crystal violet (CV) was 88.89 %, 71.09 %, and 92.75 %, respectively, at a dye concentration of 100 mg/L, pH of 6.5, and temperature of 25°C. The fungal isolate Trichoderma asperellum frequently contains chitinases, cellulose, and laccases. The findings of this study validated the potential of TA as an effective biocatalyst for the remediation of methyl orange, malachite green, and crystal violet in textile wastewater. The degradation products showed decreased toxicity to sprout seeds, such as Cicer arietinum (chickpea) and Vigna radiata (mung seeds), when compared to untreated wastewater.