Improved biodegradation potential of chlorobenzene by a mixed fungal-bacterial consortium

Abstract

A defined consortium of Ralstonia pickettii L2 (bacterium) and Trichoderma viride LW-1 (fungus) was selected to assess its potential for the enhanced biodegradation of mono-chlorobenzene (CB). At an initial concentration of 220 mg L−1 CB, the developed consortium showed an enhanced degradation rate of 0.50 mg CB·g−1protein·h−1, while the individual Ralstonia sp. L2 and Trichoderma sp. LW-1 showed average degradation rates of 0.34 and 0.32 mg CB·g−1protein·h−1, respectively. A CO2 conversion level of up to 86.3% reflected a possible high mineralization extent of CB by the co-culture. The estimated μmax and vmax values were 0.36 h−1 and 0.41 h−1 for the consortium, which were much higher than the values obtained by each strain individually. 2-Chlorophenol (2-CP) accumulated in the growth medium of strain L2 and inhibited its growth, but it could be consumed quickly by the fungus LW-1, providing a possibility to reach complete biodegradation of CB in a short time. Real-time PCR revealed that bacterium L2 played a major role in the initial stage, and that fungus LW-1 grew well if 2-CP was generated. These results suggest that the fungal-bacterial consortium might be effectively applied for complete biodegradation of CB and have a potential environmental implication in purification of CB-contaminated environments.