Transformation products of bisphenol A by a recombinant Trametes villosa laccase and their estrogenic activity

Abstract

A Trametes villosa laccase, produced as a recombinant protein in Aspergillus oryzae, was purified to an electrophoretically homogeneous state and employed in studies on the metabolism of bisphenol A. Structural analysis of the bisphenol A reaction products by the enzyme indicated that the dimer, trimer, tetramer, pentamer, and hexamer of bisphenol A with C-C and/or C-O bonds between phenol moieties, were formed as the result of successive oxidative-condensation. The reaction mixture also contained oligomers fragments, each with phenol molecules, suggesting the occurrence of cleavage of the formed oligomers to release 4-isopropenylphenol. A luciferase reporter assay using COS-7 cells revealed that both the soluble and insoluble fractions of the bisphenol A reaction products had no estrogenic activity even at rather high concentrations.

Laccase-modified silica nanoparticles efficiently catalyze the transformation of phenolic compounds

“…In order to establish a standard protocol, a reaction using free (non- immobilized) laccase in the presence of 1 mM of BPA in McIlvaine buffer (pH 5) has been carried out. As previously reported [25,27,28], the oxidative transformation of BPA in the presence of laccase leads to the production of different metabolites, which have been analyzed as presented below.…”

Enzyme Initiated Radical Polymerizations

“…Likewise halophenols [178][179][180][181][182] bisphenol A, [183][184][185] various hormones and so-called endocrine disrupting compounds [186][187][188] or even TNT [189,190] have been reported. Non-phenolic compounds may be ‗inactivated' using the LMS or PMS strategy [36,[191][192][193][194][195][196][197][198].…”

Potentiality of a ceramic membrane reactor for the laccase-catalyzed removal of bisphenol A from secondary effluents

“…Formation of 4-isopropenylphenol and 4-(2-hydroxypropan-2-yl)phenol from the degradation of BPA by other laccases or peroxidase has been reported in previous studies (Fukuda et al 2004;Huang and Weber 2005).…”

“…While 4-isopropenylphenol may be released from the degradation of the formed oligomers (Fukuda et al 2004;Uchida et al 2001), other authors have suggested that this compound may be formed in a separate biodegradation route although it may also participate in the parallel pathway of polymerization (Michizoe et al 2005). It should be noted that previous research has demonstrated that BPA products after laccase treatment lack estrogenic activity (Fukuda et al 2004;TorresDuarte et al 2012) and BPA polymerization turns into precipitates, which is favorable to reduce its environmental impact (Torres-Duarte et al 2012). In addition, with the technology presented in the current research, the discharge of BPA polymerization products in the effluent of the EMR is not expected, since they must be removed by the nanofiltration membrane.…”

“…Polymerization of BPA by laccase has been reported in previous studies, and the proposed pathway consisted of a polymerization mechanism of BPA through C-C or C-O bonds to form oligomers (Cabana et al 2007). While 4-isopropenylphenol may be released from the degradation of the formed oligomers (Fukuda et al 2004;Uchida et al 2001), other authors have suggested that this compound may be formed in a separate biodegradation route although it may also participate in the parallel pathway of polymerization (Michizoe et al 2005). It should be noted that previous research has demonstrated that BPA products after laccase treatment lack estrogenic activity (Fukuda et al 2004;TorresDuarte et al 2012) and BPA polymerization turns into precipitates, which is favorable to reduce its environmental impact (Torres-Duarte et al 2012).…”