(called ECO3) immobilized on different supports. The
co-culture was made with 3 strains:
(i) Alcaligenes sp. that uses and totally dechlorinates 3-, or
4-chlorobenzoic, and 3,4-dichlorobenzoic acids
(ii) Pseudomonas sp. capable of using and completely
dechloronating
2-chlorobenzoic
and
2,5dichlorobenzoic acids
(iii) Another strain of Pseudomonas sp. that can use
biphenyl or 4-chlorobiphenyl as sole carbon source
and cometabolize several weakly chlorinated PCBs in
the presence of biphenyl
This co-culture was immobilized on three different
supports: cubic polyurethane foam (side: 0.8 mm), glass
beads (diameter: 0.8 mm), and silica beads. Biodegradation
was more important with immobilized than with free
cells. The tested congeners (2,5-, 3,5-, 2,3
0 , 2,4
0 -, 3,3
0 -,
and 4,4
0 -dichlorobiphenyls) as well as Aroclor 1221 were
intensively degraded (48–99 %). The biodegradation
intensity varied as a function of the PCB nature and the
material. For Aroclor 1221, the dechlorination percentage
was 94.4, 79.4, and 49.2 % with polyurethane foam, glass,
and silica beads, respectively. These results prove that it is
possible to use such a consortium, immobilized, in a reactor
with fixed bed, for the treatment of wastewaters
contaminated by PCBs. Biodegradation under aerobic
conditions was also investigated upon addition of oxygen,
molecules increasing the PCB availability, or co-substrates
such as biphenyl.
Fig. 16.31 Examples of
anaerobic pathways of reductive
dechlorination observed in
sediment microcosms and
anaerobic enrichment cultures
(according Field and SierraAlvarez 2008). Dotted arrows
correspond to slow reactions;
o: ortho-dechlorination; m:
meta-dechlorination; p:
para-dechlorination.
(a) 2,2
0 ,3,3
0 ,4,4
0 ,5,6octachlorobiphenyl.
(b) 2,2
0 ,3,3
0 ,4,4
0 ,6heptachlorobiphenyl.
(c) 2,2
0 ,3,4,4
0 ,6hexachlorobiphenyl.
(d) 2,2
0 ,3
0 ,4,6pentachlorobiphenyl.
(e) 2,2
0 ,4,4
0 ,6pentachlorobiphenyl.
(f) 2,2
0 ,4,4
0 -tetrachlorobiphenyl.
(g) 2,2
0 ,4,6
0 -tetrachlorobiphenyl.
(h) Biphenyl
712
J.-C. Bertrand et al.
co-culture was made with 3 strains:
(i) Alcaligenes sp. that uses and totally dechlorinates 3-, or
4-chlorobenzoic, and 3,4-dichlorobenzoic acids
(ii) Pseudomonas sp. capable of using and completely
dechloronating
2-chlorobenzoic
and
2,5dichlorobenzoic acids
(iii) Another strain of Pseudomonas sp. that can use
biphenyl or 4-chlorobiphenyl as sole carbon source
and cometabolize several weakly chlorinated PCBs in
the presence of biphenyl
This co-culture was immobilized on three different
supports: cubic polyurethane foam (side: 0.8 mm), glass
beads (diameter: 0.8 mm), and silica beads. Biodegradation
was more important with immobilized than with free
cells. The tested congeners (2,5-, 3,5-, 2,3
0 , 2,4
0 -, 3,3
0 -,
and 4,4
0 -dichlorobiphenyls) as well as Aroclor 1221 were
intensively degraded (48–99 %). The biodegradation
intensity varied as a function of the PCB nature and the
material. For Aroclor 1221, the dechlorination percentage
was 94.4, 79.4, and 49.2 % with polyurethane foam, glass,
and silica beads, respectively. These results prove that it is
possible to use such a consortium, immobilized, in a reactor
with fixed bed, for the treatment of wastewaters
contaminated by PCBs. Biodegradation under aerobic
conditions was also investigated upon addition of oxygen,
molecules increasing the PCB availability, or co-substrates
such as biphenyl.
Fig. 16.31 Examples of
anaerobic pathways of reductive
dechlorination observed in
sediment microcosms and
anaerobic enrichment cultures
(according Field and SierraAlvarez 2008). Dotted arrows
correspond to slow reactions;
o: ortho-dechlorination; m:
meta-dechlorination; p:
para-dechlorination.
(a) 2,2
0 ,3,3
0 ,4,4
0 ,5,6octachlorobiphenyl.
(b) 2,2
0 ,3,3
0 ,4,4
0 ,6heptachlorobiphenyl.
(c) 2,2
0 ,3,4,4
0 ,6hexachlorobiphenyl.
(d) 2,2
0 ,3
0 ,4,6pentachlorobiphenyl.
(e) 2,2
0 ,4,4
0 ,6pentachlorobiphenyl.
(f) 2,2
0 ,4,4
0 -tetrachlorobiphenyl.
(g) 2,2
0 ,4,6
0 -tetrachlorobiphenyl.
(h) Biphenyl
712
J.-C. Bertrand et al.