Contents lists available at ScienceDirect Journal of Environmental Chemical Engineering journal homepage: www.elsevier.com/locate/jece Enhanced decolorization and biodegradation of acid red 88 dye by newly isolated fungus, Achaetomium strumarium Paul O. Bankole a,b, ⁎ , Adedotun A. Adekunle b , Sanjay P. Govindwar c a Department of Pure and Applied Botany, Federal University of Agriculture, Abeokuta, Ogun State, Nigeria b Department of Botany, University of Lagos, Lagos State, Nigeria c Department of Earth Resources and Environmental Engineering, Hanyang University, Seoul, 04763, South Korea ARTICLE INFO Keywords: Achaetomium strumarium Biodegradation Decolorization Acid red 88 dye Detoxification ABSTRACT Acid red 88 dye degradation efficiency of newly isolated filamentous fungus, Achaetomium strumarium were investigated. Molecular studies of 23S rRNA sequence data confirmed the phylogenetic clade relationship of the isolate with members of the same genus, Achaetomium. Achaetomium strumarium decolorized (99%) of 10 mg L -1 of acid red 88 dye at pH (4), biomass dose (2000 mg) and temperature (40 °C) within 96 h. Further studies revealed that decolorization was enhanced with the addition of calcium salts in the reaction medium resulting in maximum amount of dye adsorbed (35.55 mg g -1 ). The experimental data showed the best goodness of fit when subjected to Temkin isotherm model (R 2 = 0.985) in comparison with Freundlich and Langmuir isotherm models (R 2 = 0.883 and 0.688) respectively. The adsorption mechanism followed pseudo-second order kinetic model (R 2 = 0.997) indicating the influence of the AR88 dye molecules and fungal biomass. Enzymes analysis revealed significant inductions and role played by NADH-DCIP reductase and laccase in the asymmetric clea- vage, dehydroxylation, and desulfonation of AR-88 dye. Metabolites of the acid red 88 dye after degradation were analyzed using UV–vis spectroscopy, FTIR, HPLC and GCMS. The GCMS analysis revealed the production of three intermediates; naphthalen-2-ol, sodium naphthalene-1-sulfonate and 1,4-dihydronaphthalene. Possible metabolic fate pathway for the degradation of AR88 dye by A. strumarium was proposed. The results obtained from toxicity studies revealed the AR-88 dye detoxification efficiency of Achaetomium strumarium and hence, in its myco-transformation. 1. Introduction Azo dyes are constantly and widely applied directly or indirectly by pharmaceuticalpaper printing pulp making food leather dyeing and petroleum industries [1]. Crass pollution especially in developing na- tions arises from increasing applications of these class of dyes. Textile and dyestuff manufacturing industries account largely for the indis- criminate release of the dye into the environment [2]. Commercial synthetic dyes azo dyes inclusive represents up to 70% of the total textile dyestuffs used in industry [3]. Azo dye toxicity to plants human and animals causes grave environmental concerns owing to their characteristic brilliance color carcinogenic potentials and recalcitrance. Azo dyes recalcitrant nature is due to the possession of highly stable reactive azo bond (eN]Ne) in their structures (heterocyclic and aro- matic) [1]. High quantities of dyes are dumped into the environment as a result of rapid industrialization and urbanization. Up to half the amount of the original dye is lost to wastewater during dyeing and dye fixation processes [4]. The significant increases in oxygen demand (dissolved chemical and biological) and metals ions is largely caused by the improper discharge of dyes in water bodies [5]. Therefore to reduce the effect of these discharges it is very necessary though arduous to treat the dye effluents. Only few of several physicochemical https://doi.org/10.1016/j.jece.2018.01.069 Received 14 September 2017; Received in revised form 25 January 2018; Accepted 31 January 2018 ⁎ Corresponding author at: Department of Pure and Applied Botany, Federal University of Agriculture, P.M.B. 2240 Abeokuta, Ogun State, Nigeria. E-mail addresses: bankolepo@funaab.edu.ng, pbank54@yahoo.co.uk (P.O. Bankole). Abbreviations: UV–vis, Ultra Violet Visible spectrophotometer; FTIR, Fourier Transform Infrared spectroscopy; GCMS, Gas Chromatography Mass Spectrometry; ADMI, American Dye Manufacturer’s Institute; HPLC, High-Performance Liquid Chromatography; APHA, American Public Health Association; NADH, Nicotinamide adenine dinucleotide; DCIP, Dichlorophenol Indophenols; R, Correlation coefficient; R 2 , Coefficient of determination; S.E.M, Standard Error of Means; q e , Amount of dye adsorbed (mg g -1 ); b T , The adsorbent at the equilibrium; qt, Amount adsorbed by the adsorbent at any time (mg g -1 ); C e , Concentration of the indigo dye at the equilibrium (mg L -1 ); C o , Initial concentration of the indigo dye (mg L -1 ); n, The order of adsorption with respect to the effective concentration of the adsorption active sites present on the surface of the adsorbent; R, The universal gas constant (8.314 J K -1 mol -1 ); T, The absolute temperature at 298 (K); b T , Temkin isotherm constant,; A t , Temkin isotherm equilibrium binding constant (L g -1 ); K F , The Freundlich equilibrium constant (mg g -1 (mg L -1 ) -1/n ); n F , The Freundlich exponent (dimensionless); K L , Langmuir isotherm constant (L mg -1 ); B, Heat sorption constant (J mol -1 ); Q o , Maximum monolayer coverage capacity (mg g -1 ); k 1 , The pseudo-first-order rate constant (min -1 ); k 2 , The pseudo-second-order rate constant (g mg -1 min -1 ); t, Contact time (min) Journal of Environmental Chemical Engineering 6 (2018) 1589–1600 Available online 09 February 2018 2213-3437/ © 2018 Elsevier Ltd. 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