Pp. Luu et al., MONITORING TRICHLOROETHYLENE MINERALIZATION BY PSEUDOMONAS-CEPACIA G4PR1, Applied microbiology and biotechnology, 44(1-2), 1995, pp. 259-264
To analyze the extent of mineralization of trichloroethylene (TCE) wit
hout disturbing an actively growing biofilm, a minimal growth medium w
as formulated that reduces the concentration of chloride ions to the e
xtent that the chloride ions generated from TCE mineralization may be
detected with a chloride-ion-specific electrode. By substituting chlor
ide salts with phosphates and nitrates, a chloride-free minimal medium
was produced that yields a specific growth rate for Pseudomonas cepac
ia G4 PR1 which was 93% of that in chloride-ion-containing minimal med
ium. Furthermore, TCE degradation by resting cell suspensions was simi
lar in both media (85% of 75 mu M TCE degraded in 6 h), and complete m
ineralization of TCE was slightly superior in the chloride-free minima
l medium (77% compared to 60% of 75 mu M TCE mineralized in 6 h). In a
ddition, indole-containing, minimal-medium agar plates were developed
to indicate the presence of the TCE-degrading enzyme toluene ortho-mon
ooxygenase (fire-engine-red colonies) as well as to distinguish this e
nzyme from other TCE-degrading enzymes (toluene dioxygenase and toluen
e para-mono-oxygenase).