A facultative anaerobic bacterial strain, Bacillus sp. GZB, was isolated and identified to effectively degrade bisphenol A (BPA) under anaerobic and aerobic conditions. Under anaerobic condition, Fe3+ can be used as an electron acceptor for Bacillus sp. GZB, while 5 mg L-1 BPA can be fully removed and 51% was mineralized under optimal aerobic conditions. Additionally, seven metabolites were identified by GC-MS, four of which were doubly confirmed by authentic standards (two synthesized) and three of four initial degradation intermediates were also quantified during BPA aerobic degradation. The evolution of 1-(4-hydroxyphenyl)ethanone showed a similar tendency with estrogenic activity changing during BPA biodegradation course, indicating its potential estrogenicity. The estrogenicity temporary increase first and decline ultimately during BPA degradation revealing the GZB can effectively detoxify BPA as well as its estrogenic intermediates. This was the first study to report a facultative anaerobic strain can degrade BPA with or without of oxygen. (C) 2012 Elsevier Ltd. All rights reserved.