title: Biosorption and biodegradation of Acid Orange 7 by Enterococcus faecalis strain ZL: optimization by response surface methodological approach.
abstract: Reactive dyes account for one of the major sources of dye wastes in textile effluent. In this study, decolorization of the monoazo dye, Acid Orange 7 (AO7) by the Enterococcus faecalis strain ZL that isolated from a palm oil mill effluent treatment plant has been investigated. Decolorization efficiency of azo dye is greatly affected by the types of nutrients and the size of inoculum used. In this work, one-factor-at-a-time (method and response surface methodology (RSM) was applied to optimize these operational factors and also to study the combined interaction between them. Analysis of AO7 decolorization was done using Fourier transform infrared (FTIR) spectroscopy, desorption study, UV-Vis spectral analysis, field emission scanning electron microscopy (FESEM), and high performance liquid chromatography (HPLC). The optimum condition via RSM for the color removal of AO7 was found to be as follows: yeast extract, 0.1% w/v, glycerol concentration of 0.1% v/v, and inoculum density of 2.5% v/v at initial dye concentration of 100 mg/L at 37 °C. Decolorization efficiency of 98% was achieved in only 5 h. The kinetic of AO7 decolorization was found to be first order with respect to dye concentration with a k value of 0.87/h. FTIR, desorption study, UV-Vis spectral analysis, FESEM, and HPLC findings indicated that the decolorization of AO7 was mainly due to the biosorption as well as biodegradation of the bacterial cells. In addition, HPLC analyses also showed the formation of sulfanilic acid as a possible degradation product of AO7 under facultative anaerobic condition. This study explored the ability of E. faecalis strain ZL in decolorizing AO7 by biosorption as well as biodegradation process.
authors: Department of Biosciences and Health Sciences, Faculty of Biosciences and Medical Engineering, Universiti Teknologi Malaysia, 81310, Skudai, Johor, Malaysia.
authors: Chi Kim
authors: CK
authors: Lim
authors: Hui Han
authors: HH
authors: Bay
authors: Azmi
authors: A
authors: Aris
authors: Zaiton
authors: Z
authors: Abdul Majid
authors: Zaharah
authors: Z
authors: Ibrahim
mesh_terms: D001391:Azo Compounds / Q000032:analysis / Q000378:metabolism*; D001557:Benzenesulfonates / Q000032:analysis / Q000378:metabolism*; D001673:Biodegradation, Environmental; D002851:Chromatography, High Pressure Liquid; D004396:Coloring Agents / Q000032:analysis / Q000378:metabolism*; D013293:Enterococcus faecalis / Q000378:metabolism*; D004784:Environmental Monitoring; D007220:Industrial Waste / Q000032:analysis; D007700:Kinetics; D008855:Microscopy, Electron, Scanning; D000073878:Palm Oil; D010938:Plant Oils / Q000032:analysis / Q000737:chemistry; D015203:Reproducibility of Results; D017550:Spectroscopy, Fourier Transform Infrared; D013425:Sulfanilic Acids / Q000032:analysis / Q000378:metabolism; D013784:Textiles; D018508:Water Purification / Q000379:methods
chemical_list: D001391:Azo Compounds; D001557:Benzenesulfonates; D004396:Coloring Agents; D007220:Industrial Waste; D010938:Plant Oils; D013425:Sulfanilic Acids; D000073878:Palm Oil; C014722:2-naphthol orange