Biodegradation pathway of Acid Red 27 by white-rot fungus armillaria sp. F022 and phytotoxicity evaluation

Abstract

Armillaria sp. F022, a basidiomycete fungus isolated from a recreational forest in Johor, Malaysia, was tested for its biodegradation ability of the azo dye Acid Red 27 (AR27). Varying carbon and nitrogen sources, agitation, and inoculum concentrations on AR27 dye degradation by Armillaria sp. F022 in liquid medium were investigated to find out their effects on dye degradation. Glucose and ammonium chloride were the best nutrients for the growth of Armillaria sp. F022. The addition of 15% inoculum concentration of Armillaria sp. F022 increased the AR27 dye degradation up to 97.17% within 72h of incubation. Phytotoxicity tests were performed employing seed germination of Sorghum vulgare and Triticum aestivum by monitoring their elongation of the plumules and radicles to evaluate the toxicity of the degradation products. The metabolites formed during biodegradation were 1,4-naphthalenediol, 1,2-dihydroxynaphthalene, and coumarin, characterized by thin-layer chromatography and gas chromatography-mass spectrometry. Based on the findings of the AR27 biodegradation pathway it is proposed that Armillaria sp. F022 can be used to treat AR27 dye contaminated effluents to protect the ecosystem.