Bisphenol A degradation by Ralstonia eutropha in the absence and presence of phenol

Abstract

In the present study, a pure culture of Ralstonia eutropha was used to degrade bisphenol A (BPA). About 15–56% of BPA with the initial concentrations ranging from 1 to 20 mg l−1, was degraded. Since the bacterial culture was not able to degrade BPA completely, the phenol-adapted cells were used for the investigation of the co-metabolic degradation of BPA at concentration of 20 mg l−1 by using of phenol as the growth substrate with the concentration of 200 mg l−1. Three different approaches was used for BPA biodegradation: (i) by using it as the sole carbon source, (ii) by phenol-adapted cells (resting cells), and (iii) by growing cells in the simultaneous presence of both phenol and BPA. The removal efficiency (RE) of BPA was about 10% when it was used as the sole carbon source. RE increased to 36% by using resting cells and to 50% in the presence of phenol, simultaneously. This improvement was due to the advantages of co-metabolism due to the presence of enzymes involved in phenol degradation, which affects BPA as a co-substrate in a co-metabolic degradation process. Kinetic data for BPA biodegradation by phenol-adapted cells of R. eutropha best fitted to the Monod model. The kinetic parameters were Vmax = 7.4 (mg BPA g−1 biomass h−1) and Ks = 10.8 (mg l−1).