Decolorization Potential of Some Reactive Dyes with Crude Laccase and Laccase-Mediated System

Abstract

In this study, decolorization of dyestuffs, such as Reactive Red 198, Rem Blue RR, Dylon Navy 17, Rem Red RR, and Rem Yellow RR was studied using laccase and laccase-mediated system. The laccases are known to have an important potential for remediation of pollutants. Among these dyestuffs, decolorization of Rem Blue RR and Dylon Navy 17 was performed with crude laccase under optimized conditions. Vanillin was selected as laccase mediator after screening six different compounds with Rem Yellow RR, Reactive Red 198, and Rem Red RR as substrates. However, Rem Yellow RR was not decolorized by either laccase or laccase-mediated system. It is observed that the culture supernatant contained high laccase activity after treatment with catalase that was responsible for the decolorization. Besides, culture supernatant with high laccase activity as enzyme source was treated with catalase; in this way, the hypothesis that laccase was the enzyme responsible for decolorization was supported. The Rem Blue RR was decolorized with 64.84% under the optimum conditions and Dylon Navy 17 with 75.43% with crude laccase. However, using the laccase and vanillin, the decolorization of Reactive Red 198 and Rem Red RR was found to be 62% and 68%, respectively. Our study demonstrated that the decolorization abilities of laccase and/or laccase mediator systems were based on the types of mediator, the dye structure, and the standard experimental conditions. Also, the electrochemical behaviors of some samples were studied. The redox potentials of these samples were determined using cyclic voltammetry on glassy carbon electrode in phosphate buffer (pH 6) solution.

Decolorization of organic dye (NBB) using Fe(III)P2W12Mo5/H2O2 system

“…The NBB decreasing concentration of dye was monitored by a JENWAY UV-vis spectrophotometer. The Wave length corresponding to the maximum absorbance is given below: k max = 620 nm [13].…”

“…The oxidation efficiency (discoloration) was determined as shown below [13]: Fig. 4 illustrates the effect of pH on the discoloration efficiency of NBB in water.…”

Decolorization of Remazol Brilliant Blue R by a Purified Laccase of Polyporus brumalis

“…3), which meant laccase was positively involved in the decolorization of RBBR. Laccases have been reported in many other white rot fungi, which are involved in the degradations of diverse recalcitrant compounds such as dye [14][15][16], colored industrial wastewater [17], and endocrine-disrupting chemicals [2,9]. In some cases, laccase required a mediator for its active enzymatic reaction, but laccase 1 showed active decolorizing activity even with no mediator.…”

Facile synthesis of zero valent iron and photocatalytic application for the degradation of dyes

“…The use of synthetic dyes is increasing in dying, cosmetic, color photography parallel to the population growth. During production of dyes and dying processing, a significant amount of dyes and dyes intermediates are lost and discharged in the effluents, which are toxic and produce carcinogenic and mutagenic by-products in aqueous environment [1][2][3][4][5][6]. Dyes are the most important source of aquatic pollution.…”

“…Recently, nZVI has gained much importance as environmental catalyst for the treatment of wastewater versus other physical, biological and chemical methods [6,[14][15][16][17][18][19][20][21]. ZVI offers various advantages over other catalysts i.e., non-toxic, environmentally friendly, cost effective, easy to handle, higher surface area and enhanced reactivity [22].…”