Removal of bisphenol A by laccases from Pleurotus ostreatus and Pleurotus pulmonarius and evaluation of ecotoxicity of degradation products

Bisphenol A (BPA) is an endocrine disruptor compound, that is continuously released into the environment and is barely degraded in wastewater treatment plants. In this work, crude laccases from Pleurotus ostreatus and Pleurotus pulmonarius were used for the first time to degrade BPA in aqueous solution. The residual BPA was quantified by HPLC and the BPA metabolites produced by action of the laccases were identified by GC-MS. BPA at 100 mg/L and 200 mg/L (0.88 mmol/L) were 100% and 85% removed, respectively, in a 1 h reaction by both fungal laccases at a concentration of 8 U/L. Thirteen aromatic and aliphatic BPA metabolites were identified, including p-isopropenylphenol, methylpent-3-oic acid, ethyl-3-ethoxy propanoate, and 4-ethyl-2-methoxyphenol. The acute BPA toxicity decreased from 85% to less than 5% using the P. ostreatus laccase. On the other hand, P. pulmonarius laccase, did not caused reduction in toxicity, possibly because at least one BPA metabolite was as toxic as the parent compound itself. The results of this study suggest a feasible method for the complete removal of BPA from polluted environments using crude laccase from P. ostreatus.