Cometabolic Degradation Kinetics of Trichloroethylene Based on Toluene Enhancement by Encapsulated Burkholderia cepacia G4

The ability of encapsulated Burkholderia cepacia G4 (ATCC 53617) for trichloroethylene (TCE) degradation (1.5, 5, 10, and 20mg/L) in the presence of toluene (10 and 60mg/L) as enhancement substrate was evaluated experimentally. Burkholderia cepacia G4 cultures were encapsulated in cylindrical pellets (4mm in diameter and 4mm in height (preferred)) using polyethylene glycol (PEG). Higher transformation capacities were observed for the encapsulated cultures for both toluene concentrations. The highest transformation capacities measured for the encapsulated cultures and suspended cultures were 46.98 and 5.94mg TCE/mg biomass, respectively. TheMonod equation was used to simulate the degradation rates of toluene and Haldane’s equation was employed to describe the degradation kinetics of TCE. The first-order reaction rate constant (k/Ks) for toluene degradation in the encapsulated cultures was 2.3-fold higher than the value of the suspended cultures, whereas the kc/Ksc value for TCE was 4.3-fold higher compared to the suspended cultures. The higher kinetic values of the encapsulated cultures indicate that the degradation efficiency and capability of B. cepaciaG4was enhanced through PEG encapsulation. Moreover, the higher inhibition constant value for the encapsulated cultures compared with the suspended cultures demonstrated that PEG-encapsulated B. cepacia G4 can tolerate and degrade much higher TCE concentrations.