Induction of fungal laccase production under solid state bioprocessing of new agroindustrial waste and its application on dye decolorization

Abstract

Lignocellulosic wastes are generally produced in huge amounts worldwide. Peach waste of these obtained from fruit juice industry was utilized as the substrate for laccase production by Pleurotus eryngii under solid state bioprocessing (SSB). Its chemical composition was determined and this bioprocess was carried out under stationary conditions at 28 °C. The effects of different compounds; copper, iron, Tween 80, ammonium nitrate and manganese, and their variable concentrations on laccase production were investigated in detail. The optimum production of laccase (43,761.33 ± 3845 U L^-1) was achieved on the day of 20 by employing peach waste of 5.0 g and 70 µM Cu²⁺, 18 µM Fe²⁺, 0.025% (v/v) Tween 80, 4.0 g L^-1 ammonium nitrate, 750 µM Mn²⁺ as the inducers. The dye decolorization also researched to determine the degrading capability of laccase produced from peach culture under the above-mentioned conditions. Within this scope of the study, methyl orange, tartrazine, reactive red 2 and reactive black dyes were treated with this enzyme. The highest decolorization was performed with methyl orange as 43 ± 2.8% after 5 min of treatment when compared to other dyes. Up to now, this is the first report on the induction of laccase production by P. eryngii under SSB using peach waste as the substrate.

Keywords: Decolorization; Inducer; Laccase; Peach waste; Pleurotus eryngii; Solid state bioprocessing.

Fig. 1

The influence of copper concentrations on laccase production throughout incubation time. The values are the mean ± SD for experiments of three separate experiments

Fig. 2

The influence of iron concentrations on laccase production throughout incubation time. The values are the mean ± SD for experiments of three separate experiments

Fig. 3

The influence of Tween 80 concentrations on laccase production throughout incubation time. The values are the mean ± SD for experiments of three separate experiments

Fig. 4

The influence of ammonium nitrate concentrations on laccase production throughout incubation time. The values are the mean ± SD for experiments of three separate experiments

Fig. 5

a The influence of manganese concentrations on laccase production throughout incubation time. The values are the mean ± SD for experiments of three separate experiments. b The influence of increasing manganese concentrations on the protein and highest laccase productions. The values are the mean ± SD for experiments of three separate experiments

Fig. 6

The decolorization of some azo dyes with highest laccase activity obtained from peach culture. The values are the mean ± SD for experiments of three separate experiments