Growth factors, kinetics and biodegradation mechanism associated with Pseudomonas nitroreducens TX1 grown on octylphenol polyethoxylates.
The growth properties and biodegradation mechanism of a Gram-negative bacterium, Pseudomonas nitroreducens TX1 that was able to grow on branched octylphenol polyethoxylates (OPEO(n), average n=9.5) as the sole carbon source over a wide concentration range (1-100,000 mgl(-1)) were studied. Analysis of growth factors indicated the highest specific growth rate (micro) of 0.53 h(-1) was obtained at an initial concentration of 5,000 mgl(-1) OPEO(n). An optimal C/N ratio of 12 was obtained for (NH(4))(2)SO(4) as the nitrogen source in a cultivated medium at pH 7. The kinetic analysis demonstrated that bacterial growth and OPEO(n) degradation followed the Monod equation and were based on a substrate concentration inhibition model and pseudo-first-order reaction, respectively. The substrate inhibition coefficient was over 18,000 mgl(-1) and this indicates that the strain has an ability to sustain growth at high concentrations of OPEO(n) and use it as the sole carbon source under such a stress condition. Furthermore, LC-MS analysis showed that the biodegradation mechanism of dodecyl octaethoxylate (AEO8) by P. nitroreducens TX1 was the sequential cleavage of the ethoxylate chain.
Graduate Institute of Environmental Engineering, National Central University, Chung-Li, Taiwan, ROC. hjchen@mail.ev.ncu.edu.tw
Hsi-Jien
HJ
Chen
Gia-Luen
GL
Guo
Dyi-Hwa
DH
Tseng
Chen-Li
CL
Cheng
Shir-Ly
SL
Huang
D049109:Cell Proliferation; D006863:Hydrogen-Ion Concentration; D036341:Intercellular Signaling Peptides and Proteins / Q000378:metabolism*; D007700:Kinetics; D013058:Mass Spectrometry; D015394:Molecular Structure; D009584:Nitrogen / Q000378:metabolism; D010880:Piperidines / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry* / Q000378:metabolism*; D011549:Pseudomonas / Q000166:cytology* / Q000378:metabolism*
D036341:Intercellular Signaling Peptides and Proteins; D010880:Piperidines; D011108:Polymers; C039611:octapinol; D009584:Nitrogen