Biodegradation of bisphenol A and 4-alkylphenols by Novosphingobium sp. strain TYA-1 and its potential for treatment of polluted water

Abstract

We investigated the use of Novosphingobium sp. strain TYA-1 for the simultaneous removal of bisphenol A (BPA) and 4-alkylphenols (4-APs) from complex polluted waters. Strain TYA-1 degraded BPA and utilized it as a sole carbon and energy source via oxidative skeletal rearrangement involving the cytochrome p450 monooxygenase system. Strain TYA-1 also degraded 4-APs with branched side alkyl chains (4-tert-butylphenol [4-tert-BP], 4-sec-butylphenol, 4-tert-pentylphenol, 4-tert-octylphenol [4-tert-OP], and branched nonylphenol mixture) via 4-alkylcatechols but could not degrade 4-APs with linear side alkyl chains. Degradation of 4-APs, like that of BPA, involved the cytochrome p450 monooxygenase system in strain TYA-1. A sequencing batch bioreactor (100 mL of polluted water [50 mg/L BPA, 50 mg/L 4-tert-BP, and 5 mg/L 4-tert-OP]; 6 h of reaction time/cycle; 12 cycles in total) containing alginate-immobilized TYA-1 cells (15 mg dry cells) simultaneously removed BPA, 4-tert-BP, and 4-tert-OP from complex polluted waters. These immobilized TYA-1 cells could be reused for a total of 9 cycles without any loss of degradation activity. Our results support the potential of using immobilized TYA-1 cells for the simultaneous removal of BPA and 4-APs from complex polluted waters.