TRICHLOROETHYLENE DEGRADATION AND MINERALIZATION BY PSEUDOMONADS AND METHYLOSINUS-TRICHOSPORIUM OB3B

To examine the trichloroethylene (C2HCl3)-degrading capability of five microorganisms, the maximum rate, extent, and degree of C2HCl3 minera lization were evaluated for Pseudomonas cepacia G4, Pseudomonas cepaci a G4 PR1, Pseudomonas mendocina KR1, Pseudomonas putida F1, and Methyl osinus trichosporium OB3b using growth conditions commonly reported in the literature for expression of oxygenases responsible for C2HCl3 de gradation. By varying the C2HCl3 concentration from 5 mu M to 75 mu M, V-max and K-m values for C2HCl3 degradation were calculated as 9 nmol /(min mg protein) and 4 mu M for P. cepacia G4, 18 nmol/(min mg protei n) and 29 mu M for P. cepacia G4 PR1, 20 nmol/(min mg protein) and 10 mu M for P. mendocina KR1, and 8 nmol/(min mg protein) and 5 mu M for P. putida Fl. This is the first report of these Michaelis-Menten param eters for P. mendocina KR1, P. putida F1, and P. cepacia G4 PR1. At 75 mu M, the extent of C2HCl3 that was degraded after 6 h of incubation with resting cells was 61%-98%; the highest degradation being achieved by toluene-induced P. mendocina KR1, The extent of C2HCl3 mineralizat ion in 6 h (as indicated by concentration of chloride ion) was also me asured and varied from 36% for toluene-induced P. putida Fl to 102% fo r M. trichosporium OB3b. Since C2HCl3 degradation requires new bio-mas s, the specific growth rate (mu(max)) of each of the C2HCl3-degradatio n microorganisms was determined and varied from 0.080/h (M. trichospor ium OB3b) to 0.864/h (P. cepacia G4 PR1).