Environmental Engineering Reference
In-Depth Information
A
Mix C
300
200
100
0
1234
567
B
Mix C + NY05
NY05
300
300
200
200
100
100
0
0
0
6
12
Time, h
18
24
1234
567
RHA1
Mix C + RHA1
300
300
200
200
100
100
0
0
0
6
12
Time, h
18
24
1234
567
LB400
Mix C + LB400
300
300
200
200
100
100
0
0
0
6
12
Time, h
18
24
1234
567
Figure 6.8
Degradation of
m
ix C by BP degraders.
para-directed strains NY05 and VP44 was especially significant from 2,4-CB
and 2,4,4-CB. Biochemical assay suggested that these chlorinated interme-
diates reversibly inhibit hydrolase activity, preventing complete transforma-
tion of the HOPDAs to the respective chlorobenzoates (Maltseva et al., 1999).
Aerobic degradation of PCBs by biphenyl-growing bacteria is usually
cometabolic and results in partial degradation, particularly the accumulation
of chlorobenzoates (Abramowicz, 1990; Unterman, 1996). Introduction of
genes for dehalogenases that control removal of chlorine from ortho- and
para-chlorinated benzoates into PCB-cometabolizing strains should result in
growth of the recombinant bacteria on the targeted ortho- and ortho- +
para-substituted congeners. The ideal host for constructing genetically mod-
ified microorganisms that would grow on anaerobic Aroclor dechlorination
products should:
