Microbial Decolorization of an Azo Dye Reactive Black 5 Using White-Rot Fungus Pleurotus eryngii F032

Abstract

The growth of white-rot fungus Pleurotus eryngii F032 in a suitable medium can degrade an azo dye Reactive Black 5 (RB5), because of its ability to produce ligninolytic enzymes such as lignin peroxidase (LiP), manganese peroxidase (MnP), and laccase that able to degrade and transform the complex structure of the dye into a less toxic compound. The effect of environmental factors such as initial concentration of Reactive Black 5, pH, temperature of growth medium, surfactant (Tween 80), and agitation were also investigated. The productions of ligninolytic enzymes were enhanced by increasing the white-rot fungi growth in optimum conditions. The decolorization of Reactive Black 5 were analyzed by using UV-vis spectrophotometer at the maximum absorbance of 596 nm. The whiterot fungus, P. eryngii F032 culture exhibited 93.56 % decolorization of 10 mg/L RB5 within 72 h of incubation in dark condition with agitation. The optimum pH and temperature for the decolorizing activity was recorded at pH 3 and 40°C, respectively. The addition of surfactant (Tween 80) increased the decolorization to 93.57 % and agitation of growth medium at 120 rpm enhanced the distribution of nutrients to the fungus thus optimized the enzymatic reaction that resulted maximum decolorization of RB5 which was 93.57 %. The molecular docking studies were performed using Chimera visualization software as to analyze the decolorization mechanism of RB5 at molecular level.

Decolorization of Six Synthetic Dyes by Fungi

“…Trametes pubescens decolorizes Reactive Red 243 (azo dye) and Remazol Brilliat Blue R (anthraquinone dye) (Casieri et al, 2008). Our results and the results in literature (Swamy and Ramzay, 1999;Hadibarata et al, 2013;Eichlerova et al, 2006;Máximo et al, 2003;Palmieri et al, 2005;Mechichi et al, 2006;Casieri et al, 2008) show that Remazol Brilliant Blue R, Remazol Brilliant Orange 3 R, Reactive Blue 4, Remazol Brilliant Red F3B and Reactive Black 5 are all decolorized by at least some lignin degrading whiterot basidiomycetes. We conclude that Remazol Brilliant Yellow GL is persistent and can therefore cause harmful impacts in the environment.…”

“…Typical versatile peroxidases are produced by Pleurotus eryngii (Ruiz-Dueñas et al, 2009). Another strain of P. eryngii F032 decolorizes Reactive Black 5 in liquid medium, while producing lignin peroxidase (LiP), manganese peroxidase (MnP) and laccase (Hadibarata et al, 2013), but versatile peroxidase activity was not determined. D. squalens is able to decolorize Orange G, Amaranth, Orange I, Remazol Brilliant Blue R (RBBR), Cu-phthalocyanin, Poly R-478, Malachite Green and Crystal Violet on agar plates (Eichlerova et al, 2006).…”

Biological Treatment of Reactive Black 5 by Resupinate White Rot Fungus Phanerochaete sordida PBU 0057

“…Degradation of the dye was monitored spectrophotometrically from 400 to 700 nm [26], and by HPLC analysis [36]. The decolorized dye products were assessed by comparison of spectrophotometric peaks every 24 hours to those of RB5 (control).…”

“…Manganese peroxidase and laccase have previously been linked directly to the degradation of aromatic compounds, including decoloration of synthetic dyes by white rot fungi [2,11,18,26]. However, dyes containing highly recalcitrant structures could limit the decoloration ability of the fungus since they require higher redox potential of a catalyst to initiate electron distribution in a degradation mechanism [6,16,17].…”

“…Broader studies of this resupinate group address their biodegradative capabilities [10], and specifi c focus has centered on Dichomitus squalens, Irpex lacteus, and Bjerkandera adusta [2,[20][21][22]. Resupinate white rots occur widely in tropical countries, including Thailand [23][24][25], and although their wood degradation was considered [26], their potential role in bioremediation has yet to be fully addressed.…”