TY - JOUR
T1 - Biodegradation during contaminant transport in porous media
T2 - 4. Impact of microbial lag and bacterial cell growth
AU - Sandrin, Susannah K.
AU - Jordan, Fiona L.
AU - Maier, Raina M.
AU - Brusseau, Mark L.
N1 - Funding Information:
This research was supported by grants provided by the National Science Foundation Environmental Geochemistry Program and the Environmental Protection Agency Joint Bioremediation Program.
PY - 2001
Y1 - 2001
N2 - Miscible-displacement experiments were conducted to examine the impact of microbial lag and bacterial cell growth on the transport of salicylate, a model hydrocarbon compound. The impacts of these processes were examined separately, as well as jointly, to determine their relative effects on biodegradation dynamics. For each experiment, a column was packed with porous medium that was first inoculated with bacteria that contained the NAH plasmid encoding genes for the degradation of naphthalene and salicylate, and then subjected to a step input of salicylate solution. The transport behavior of salicylate was non-steady for all cases examined, and was clearly influenced by a delay (lag) in the onset of biodegradation. This microbial lag, which was consistent with the results of batch experiments, is attributed to the induction and synthesis of the enzymes required for biodegradation of salicylate. The effect of microbial lag on salicylate transport was eliminated by exposing the column to two successive pulses of salicylate, thereby allowing the cells to acclimate to the carbon source during the first pulse. Elimination of microbial lag effects allowed the impact of bacterial growth on salicylate transport to be quantified, which was accomplished by determining a cell mass balance. Conversely, the impact of microbial lag was further investigated by performing a similar double-pulse experiment under no-growth conditions. Significant cell elution was observed and quantified for all conditions/systems. The results of these experiments allowed us to differentiate the effects associated with microbial lag and growth, two coupled processes whose impacts on the biodegradation and transport of contaminants can be difficult to distinguish.
AB - Miscible-displacement experiments were conducted to examine the impact of microbial lag and bacterial cell growth on the transport of salicylate, a model hydrocarbon compound. The impacts of these processes were examined separately, as well as jointly, to determine their relative effects on biodegradation dynamics. For each experiment, a column was packed with porous medium that was first inoculated with bacteria that contained the NAH plasmid encoding genes for the degradation of naphthalene and salicylate, and then subjected to a step input of salicylate solution. The transport behavior of salicylate was non-steady for all cases examined, and was clearly influenced by a delay (lag) in the onset of biodegradation. This microbial lag, which was consistent with the results of batch experiments, is attributed to the induction and synthesis of the enzymes required for biodegradation of salicylate. The effect of microbial lag on salicylate transport was eliminated by exposing the column to two successive pulses of salicylate, thereby allowing the cells to acclimate to the carbon source during the first pulse. Elimination of microbial lag effects allowed the impact of bacterial growth on salicylate transport to be quantified, which was accomplished by determining a cell mass balance. Conversely, the impact of microbial lag was further investigated by performing a similar double-pulse experiment under no-growth conditions. Significant cell elution was observed and quantified for all conditions/systems. The results of these experiments allowed us to differentiate the effects associated with microbial lag and growth, two coupled processes whose impacts on the biodegradation and transport of contaminants can be difficult to distinguish.
KW - Bacteria
KW - Biodegradation
KW - Contaminant transport
KW - Organic compounds
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U2 - 10.1016/S0169-7722(01)00112-7
DO - 10.1016/S0169-7722(01)00112-7
M3 - Article
C2 - 11523326
AN - SCOPUS:0034921848
SN - 0169-7722
VL - 50
SP - 225
EP - 242
JO - Journal of Contaminant Hydrology
JF - Journal of Contaminant Hydrology
IS - 3-4
ER -