Anaerobic biodegradation of 2,4-dinitrotoluene by Rhodobacter sphaeroides

Abstract:

[Objective] To investigate the biodegradation of 2,4-dinitrotoluene (2,4-DNT) under various environmental conditions by Rhodobacter sphaeroides. [Methods] 2,4-DNT was anaerobically biodegraded under 30 °C in illumination incubator using photosynthetic bacterium Rhodobacter sphaeroides. The concentration of 2,4-DNT in liquid medium were detected by HPLC. [Results] Optimum conditions for the removal of 2,4-DNT were initial concentration of 40 mg/L, initial pH 7.0 and inoculation quantity of 15%. In addition, 2,4-DNT could be absorbed by the cells in lag phase, then degraded as carbon source in exponential phase. The removal rate of 2,4-DNT achieved 98.8% at 72 h. Using HPLC, two different intermediate metabolites were also observed, however, these decreased gradually within 120 h. Furthermore, the removal kinetics of 2,4-DNT corresponded with the first-order rate model. [Conclusion] The removal rate of 2,4-DNT under different conditions indicated that Rhodobacter sphaeroides is efficient in biodegrading 2,4-DNT.