Removal of bisphenol derivatives through quinone oxidation by polyphenol oxidase and subsequent quinone adsorption on chitosan in the heterogeneous system

Abstract

In this study, the combined use of a biopolymer chitosan and an oxidoreductase polyphenol oxidase (PPO) was systematically investigated for the removal of bisphenol derivatives from aqueous medium. The process parameters, such as the pH value, temperature, and PPO concentration, were estimated to conduct the enzymatic quinone oxidation of bisphenol derivatives by as little enzyme as possible. Bisphenol derivatives effectively underwent PPO-catalysed quinone oxidation without H2O2 unlike other oxidoreductases, such as peroxidase and tyrosinase, and the optimum conditions were determined to be pH 7.0 and 40°C for bisphenol B, bisphenol E, bisphenol O, and bisphenol Z; pH 7.0 and 30°C for bisphenol C and bisphenol F; and pH 8.0 and 40°C for bisphenol T. They were completely removed through adsorption of enzymatically generated quinone derivatives on chitosan beads or chitosan powders. Quinone adsorption on chitosan beads or chitosan powders in the heterogeneous system was found to be a more effective procedure than generation of aggregates in the homogeneous system with chitosan solution. The removal time was shortened by increasing the amount of chitosan beads or decreasing the size of the chitosan powders.

Chitosan: An Update on Potential Biomedical and Pharmaceutical Applications

“…Chitosan along with polyphenol oxidase were used in conjunction for eliminaton of bisphenol derivatives from aqueous solutions based on adsorption of enzymatically generated quinine derivatives on chitosan beads or chitosan powders. The optimum temperature and pH conditions were 40 °C and pH 7 for bisphenols B, E, O, and Z; 30 °C and pH 7 for bisphenols C and F; and 40 °C and pH 8 for bisphenol T. The removal time could be reduced by using more chitosan beads or chitosan powders of a smaller size [ 135 ]. Sorption of Cd(II) ions onto cross-linked low-molecular-weight chitosan pyruvic acid derivative followed Langmuir isotherm model and displayed pseudo second-order kinetics.…”

Removal of Linear and Branched Alkylphenols with the Combined Use of Polyphenol Oxidase and Chitosan

“…The appearance of the absorbance at 400 nm showed that the alkylphenols used underwent PPO-catalyzed quinone oxidation in the same manner as the case when mushroom and Aspergillus tyrosinases were used [20,21,22,23,33,34]. This meant that the catechol intermediates were converted into the corresponding quinone derivatives by the catecholase activity of PPO.…”

“…Effects of enzyme concentration on PPO-catalyzed quinone oxidation of 14 kinds of linear and branched alkylphenols were investigated at pH 7.0 and 40 °C (Table 1). These values were determined as the optimum conditions of PPO used in this study for BPA and its derivatives in our previous articles [33,34]. Therefore, these optimum conditions were used for PPO-catalyzed quinone oxidation in this study.…”

“…Stock solutions of alkylphenols and PPO were prepared in a pH 7.0 phosphate buffer (ionic strength = 0.01 M) at prescribed concentrations [33,34]. Chitosan beads were washed with buffer several times and then preserved in buffer before adsorption experiments.…”

“…An alternative oxidoreductase, polyphenol oxidase (PPO), has been reported to catalyze quinone oxidation of phenol compounds [29,30,31,32]. They were removed with the combined use of PPO and chitosan [33,34].…”