Characterization of a newly isolated biphenyl-degrading bacterium, Dyella ginsengisoli LA-4.

A novel biphenyl-degrading bacterium, Dyella ginsengisoli LA-4 was isolated from activated sludge. This isolate could utilize biphenyl as sole source of carbon and energy. The resting cells of strain LA-4 could utilize 100 mg/L biphenyl within 20 h, and they were able to degrade 500 mg/L biphenyl within 40 h. The surfactant, Tween 80, could accelerate the biodegradation process. The increase of NaCl concentration inhibited the biphenyl degradation. No biphenyl degradation was detected when the NaCl concentration exceeds 10%. The effects of metal ions on biphenyl degradation were investigated. The results indicated that metal ions such as Cu(2+), Mn(2+), and Co(2+) could completely inhibit the biodegradation of biphenyl, but Mg(2+), Ca(2+), and Zn(2+) had no effects on the degradation of biphenyl. The removal rate was about 64% and 37% in the presence of Fe(3+) and Ni(2+), respectively. This study suggested that strain LA-4 could be widely used for bioremediation of soil and wastewater contaminated by biphenyl, NaCl, and metal ions.