Environmental Engineering Reference
In-Depth Information
surfactants that are compatible with the engineered bacteria discussed below,
including
Rhodococcus erythreus
NY05,
Rhodococcus
RHA1, and
Comamonas
testosteroni
VP44. The experimental approach involved a systematic screen-
ing of selected surfactants in microbial batch systems for toxicity or inhibi-
tory effects, prior to the addition of engineered bacteria and surfactant to a
contaminated soil or sediment system. The ideal surfactant candidate would
not be readily utilized as a growth substrate by the bacteria, possibly serving
as a preferential growth substrate over PCBs or reducing the selective pres-
sure for PCB growth genes. In addition to biological compatibility, the
selected surfactants were also tested for sorptive losses to several natural
soils, capacity to solubilize PCB congeners, coupled solubilization and micro-
bial transformation, and effects on plasmid stability.
The third objective focused on pilot-scale implementation of PCB biore-
mediation using soil collected from Lake Ontario Ordinance Works (LOOW)
Picatinny Arsenal and General Electric at a site located in Rome, GA. The
practical effectiveness of a two-phase anaerobic-aerobic bioremediation sys-
tem was evaluated in cooperation with engineers in the Strategic Environ-
mental Research and Development Program (SERDP) bioconsortium at
Georgia Tech and the Waterways Experiment Station (WES).
6.2.2
Research objectives to design PCB-growing GEMs
•
Develop gene cloning and chromosomal integration technique in
Rhodococcus
strains.
•
Design genetically enhanced para- and ortho-PCB-growing
gram-negative and
Rhodococcus
strains.
•
Evaluate the fate of the designed organisms and their effect on PCBs
in soils.
•
Develop methods allowing the tracking of introduced organisms and
genes
in situ
.
•
Evaluate effect of anaerobic-aerobic shift and FeSO
4
and FeS on sur-
vivability and PCB degradative activity of the designed organisms
in soils.
•
Develop suitable protocol for soil inoculation with the engineered
microorganisms.
•
Enhance anaerobic reductive PCB dechlorination in PCB-contaminat-
ed soil.
•
Evaluate the recombinant PCB remediation two-phase technology on
the pilot scale using PCB-contaminated soils.
•
Evaluate the feasibility of anaerobic PCB dechlorination in contami-
nated soils to enrich the congeners that would be accessible for deg-
radation by aerobic genetically enhanced microorganisms.
•
Establish methods allowing rapid and quantitative detection of ge-
netically engineered PCB-growing bacteria
in situ
.
