Predation and inhibitors in lake water affect the success of inoculation to enhance biodegradation of organic chemicals

Zaidi, Baqar R.; Murakami, Yoshitaka; Alexander, Martin

doi:10.1021/es00065a016

Cited by 37 publications

(19 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The biodegradation data indicate that when protozoan activity is suppressed, biodegradation is enhanced, presumably due to the removal of one regulator of bacterial growth. Similar observations have been reported for p-nitrophenol biodegradation in lake water [44,45].…”

Section: Aerobic Experimentssupporting

confidence: 90%

Influence of protozoan grazing on contaminant biodegradation

Kota

1999

FEMS Microbiology Ecology

View full text Add to dashboard Cite

The influence of protozoan grazing on biodegradation rates in samples from contaminated aquifer sediment was evaluated under aerobic and anaerobic conditions. Predator–prey biomass ratios suggested that protozoan grazing might be influencing bacterial populations. Experiments under aerobic conditions were conducted with a sediment extract fed with BTEX and treated with protozoan inhibitors (cycloheximide, neutral red, amphotericin‐B). After 10 days, BTEX losses were enhanced in the presence of protozoan inhibitors, suggesting that reduced protozoan grazing enhanced the rate of BTEX biodegradation. In tests conducted in macrocosms under anaerobic conditions, treatments included benzaldehyde (carbon substrate), benzaldehyde+cycloheximide, a live control (no carbon), and an abiotic control. In both the benzaldehyde‐only and benzaldehyde+cycloheximide treatments, repeated benzaldehyde additions resulted in an increase in the total fermenter population from 103 to 105 cells (g sediment)−1 and in the Fe‐reducing population from 101 to 105 cells g−1. However, the protozoan population remained at about 20 cells g−1 in the sediment with no cycloheximide, and there was no difference in benzaldehyde biodegradation in the presence and absence of cycloheximide, suggesting that predation was not a significant control on anaerobic benzaldehyde biotransformation.

show abstract

Section: Aerobic Experimentssupporting

confidence: 90%

Influence of protozoan grazing on contaminant biodegradation

Kota

1999

FEMS Microbiology Ecology

View full text Add to dashboard Cite

show abstract

“…It has been hypothesized that microorganisms isolated from systems of high contaminant concentration may not be able to degrade organic contaminants at the significantly lower concentrations commonly found in aquifer systems and sediments (Alexander, 1985). Inoculation studies in aquatic systems with p-nitrophenol (PNP) have shown mineralization at concentations above 50/~g 1 -~, but only 35% mineralization when concentrations of PNP were 26/~g 1 -~ or less (Zaldi et al, 1989). To test this hypothesis, the experiments described above were repeated at low hydrocarbon concentrations.…”

Section: Resultsmentioning

confidence: 99%

Inoculation of contaminated subsurface soils with enriched indigenous microbes to enhance bioremediation rates

Weber

Corseuil

1994

Water Research

View full text Add to dashboard Cite

The inoculation of subsurface soils with enriched indigenous microbes to enhance bioremediation is described. The technique, designed to rapidly increase subsurface populations of specific microorganisms, is tested in laboratory soil columns using benzene, toluene and xylene as organic target compounds and a natural aquifer sand as a subsurface medium. A short biologically active carbon adsorber is demonstrated to be an efficient reactor system for the growth, acclimation and enrichment of indigeous microorganisms for re-inoculation purposes. Empty-bed reactor contact times of approx. 40 s are shown to be sufficient for continuous production of effluent streams of enriched indigenous microbes for re-inoculation. The ability of the technique to rapidly increase populations of such microbes to levels above 105 cells g-~ of dry solids in the previously uncontaminated aquifer sand studied is shown to result in enhanced rates of in situ degradation of the target hydrocarbons over a broad range of concentrations, from 25 to 9000/~g 1 -I.

show abstract

“…Failure of bacterial inoculation to enhance biodegradation in aquatic environments and in soil was shown to be attributable to biological factors such as protozoal predation preventing cell multiplication (Habte and Alexander 1977;Wiggins et al 1987;Ramadan et al 1990), chemical factors such as limitation of nutrients (Wiggins et al 1987; Ram a d a n et al. 1990), limitation in c o n t a m i n a n t concentration (Zaidi et al 1988), inhibition by toxic c o m p o u n d s (Wiggins and Alexander 1988;Zaidi et al 1989) and physical factors such as diffusion limitation of bacteria into soil (Goldstein et al 1985).…”

Section: Introductionmentioning

confidence: 99%

Role of inoculum preparation and density on the bioremediation of 2,4-D-contaminated soil by bioaugmentation

Comeau

Greer

Samson

1993

Appl Microbiol Biotechnol

View full text Add to dashboard Cite

The effect of inoculum preparation and density on the efficiency of remediation of 2,4-dichlorophenoxyacetic acid (2,4-D) by bioaugmentation was studied in non-sterile soil. A 2,4-D-degrading Pseudomonas cepacia strain (designated BRI6001) was used initially in liquid culture to determine the effects of pre-growth induction and of inoculum density. The time for complete 2,4-D degradation was reduced by 0.5 day for each log increase of inoculum density. In mixed (BRI6001 and soil bacteria) liquid cultures, a competition effect for 2,4-D became apparent at low inoculum levels (less than 105 cfu/ml BRI6001 for 108 cfu/ml soil bacteria) but only when the soil bacteria included indigenous 2,4-D degraders. In static non-sterile soil, the effect of inoculum density on 2,4-D degradation was comparable to that in liquid culture but only at high inoculation levels. At lower levels, a biological effect for 2,4-D degradation became apparent, as was observed in mixed liquid cultures, whereas at intermediate levels, a combination of biological, physical and chemical factors decreased the efficiency of bioaugmentation. The acclimation period for 2,4-D degradation in soil bioaugmented with BRI6001 reflected mainly the time required for cell induction and, presumably, for overcoming the physical limitation of diffusion of both 2,4-D and added bacteria in the soil matrix.

show abstract

Predation and inhibitors in lake water affect the success of inoculation to enhance biodegradation of organic chemicals

Cited by 37 publications

References 11 publications

Influence of protozoan grazing on contaminant biodegradation

Influence of protozoan grazing on contaminant biodegradation

Inoculation of contaminated subsurface soils with enriched indigenous microbes to enhance bioremediation rates

Role of inoculum preparation and density on the bioremediation of 2,4-D-contaminated soil by bioaugmentation

Contact Info

Product

Resources

About