A comparative study of an industrial effluent treatment using enzymatic and alkaline adapted consortium assays

Abstract

BACKGROUND: Dyeing effluents are the main source of water pollution from textile industries. Consequently, the treatment of such effluents is of environmental concern. RESULTS: Decolorization of a textile industry effluent was investigated using, for the first time, the trimeric Scytalidium thermophilum laccase without mediator addition. The maximum effluent decolorization (50%) was achieved after 8 h using a diluted effluent (5 fold) and 4 units of crude enzyme, operating at 50 °C and pH 4. Characterization of raw effluent presents two peaks as demonstrated by the UV‐visible spectrum, showing an intensive peak around 670 nm and a smaller one at 290 nm. At the end of the enzymatic treatment, these two peaks disappeared and a new peak emerged at 280 nm. Because laccase catalyzed effluent decolorization percentage did not exceed 50%, an alkaline adapted consortium treatment assay of this effluent was carried out. An alkaline adapted consortium was used at bench scale in order to decolorize the raw effluent. After 24 h of exposure, color and COD (chemical oxygen demand) removal rates reached 73% and 71%, respectively, at pH 11. CONCLUSION: The adapted consortium treatment of the industrial effluent is economically very interesting since the treatment is costless and can be applied at pilot or industrial scales. © 2012 Society of Chemical Industry

Detoxification of Indigo carmine using a combined treatment via a novel trimeric thermostable laccase and microbial consortium

“…However, its ability to completely remove color is limited [5]. Besides the reduction of environmental pollution, enzymatic decolorization of dyeing effluents has been recently shown to enable the reuse of the treated water in the dyeing process and thus to reduce water consumption [2,6].…”

“…These methods were used as pretreatments or employed after biological depuration. However, this practice is in the origin of a substantial environmental pollution and damages the human health [1].…”

“…Dyeing effluents are the main source of water pollution by textile industries [1]. Synthetic dyes present a special class of pollutants.…”

“…Small amounts of them are released into the environment, where they are easily perceivable and some of them are still toxic. Many researches were performed aiming the decolorization of dyestuff in effluents by various physical, chemical and biological processes [2]. Decolorization of industrial textile wastewater was achieved by ozonization, flocculation-filtration and alkalinization using calcium hydrosulfite [3,4].…”

“…The biodegradation of Indigo carmine, one of the major natural environments contaminating dyes, was carried out by a variety of microorganisms including alkalophilic, thermophilic, and anaerobic bacteria [8]. However, physical or chemical processes were shown to be ineffective for the degradation or removal of Indigo carmine [2]. The decolorization of such dye was also evidenced for fungi in particular wood-rooting fungi whose oxidative enzymes involved in the ligninolytic systems are the most important effectors suited for enzymatic dye degradation [9].…”