Biomedical Engineering Reference
In-Depth Information
Figure 7.1. cis-DCE that accumulates from incomplete reductive dechlorination can be completely
mineralized by Polaromonas sp. JS666.
Despite such obstacles, the cometabolic oxidation of
cis
-DCE has been demonstrated in the
field (Azizian et al.,
2005
,
2007
; Semprini et al.,
1990
,
2007
).
Polaromonas
sp. strain JS666 is the first isolate capable of using
cis
-DCE as its sole carbon
and energy source under aerobic conditions (Coleman et al.,
2002a
). It is a promising candidate
for bioaugmentation at
cis
-DCE-contaminated sites where
cis
-DCE has migrated downgradient
into an aerobic zone (Figure
7.1
). Addition of the strain can circumvent the problems associated
with cometabolic oxidation as a bioremediation strategy because it catalyzes rapid degradation
without the addition of a cosubstrate, and the requirements for oxygen are much lower than for
cometabolic transformations. The metabolic capabilities of JS666, development of a molecular
probe for process monitoring, microcosm assessment of site suitability and the preliminary
results of a field-scale study are discussed in this chapter.
7.2
POLAROMONAS
SP. STRAIN JS666
Preliminary evidence for the aerobic oxidation of
cis
-DCE was noted in stream-bed
sediments (Bradley and Chapelle,
1998a
,
b
), and the microbial mineralization of
cis
-DCE
was confirmed by the sequential transfer of the sediment from microcosms to defined
medium (Bradley and Chapelle,
2000
). The organism(s) responsible for
cis
-DCE transforma-
tion in the sediment were not identified, however, because
cis
-DCE concentrations were too
low to support significant growth (Bradley and Chapelle,
2000
). The results provided the first
evidence that
cis
-DCE could serve as a primary substrate in aerobic metabolism.
Search WWH ::
Custom Search