title: Biodecolorization of recalcitrant dye as the sole sourceof nutrition using Curvularia clavata NZ2 and decolorization ability of its crude enzymes.
abstract: Extensive use of recalcitrant azo dyes in textile and paper industries poses a direct threat to the environment due to the carcinogenicity of their degradation products. The aim of this study was to investigate the efficiency of Curvularia clavata NZ2 in decolorization of azo dyes. The ability of the fungus to decolorize azo dyes can be evaluated as an important outcome as existing effluent treatment is unable to remove the dyes effectively. C. clavata has the ability to decolorize Reactive Black 5 (RB5), Acid Orange 7 (AO7), and Congo Red azo dyes, utilizing these as sole sources of carbon and nitrogen. Ultraviolet-visible (UV-vis) spectroscopy and Fourier infrared spectroscopy (FTIR) analysis of the extracted RB5's metabolites along with desorption tests confirmed that the decolorization process occurred due to degradation and not merely by adsorption. Enzyme activities of extracellular enzymes such as carboxymethylcellulase (CMCase), xylanase, laccase, and manganese peroxidase (MnP) were also detected during the decolorization process. Toxicity expressed as inhibition of germination was reduced significantly in fungal-treated azo dye solution when compared with the control. The cultivation of C. clavata under sequential batch system also recorded a decolorization efficiency of above 90%. The crude enzyme secreted by C. clavata also showed excellent ability to decolorize RB5 solutions with concentrations of 100 ppm (88-92%) and 1000 ppm (70-77%) without redox mediator. This proved that extracellular enzymes produced by C. clavata played a major role in decolorization of RB5.
authors: Institute of Environmental and Water Resource Management, Water Research Alliance, Universiti Teknologi Malaysia, 81310, Skudai, Johor, Malaysia.
authors: Chin Hong
authors: CH
authors: Neoh
authors: Chi Yong
authors: CY
authors: Lam
authors: Chi Kim
authors: CK
authors: Lim
authors: Adibah
authors: A
authors: Yahya
authors: Hui Han
authors: HH
authors: Bay
authors: Zaharah
authors: Z
authors: Ibrahim
authors: Zainura Zainon
authors: ZZ
authors: Noor
mesh_terms: D001203:Ascomycota / Q000166:cytology / Q000187:drug effects / Q000201:enzymology* / Q000378:metabolism; D001391:Azo Compounds / Q000737:chemistry / Q000378:metabolism* / Q000633:toxicity; D003116:Color; D005110:Extracellular Space / Q000201:enzymology; D013784:Textiles; D014874:Water Pollutants, Chemical / Q000737:chemistry / Q000378:metabolism* / Q000633:toxicity
chemical_list: D001391:Azo Compounds; D014874:Water Pollutants, Chemical