Inoculants and Biodegradation of Crude Oil Floating on Marsh Sediments

Neralla, S.; Weaver, R. W.

doi:10.1080/10889869709351320

Cited by 16 publications

(6 citation statements)

References 17 publications

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“…The authors observed unpredictable variability in the natural inoculum, which was a limitation to accurate and reproducible assessment of commercial products. Neralla and Weaver [12] tested ten commercial products in salt marsh microcosms over a 90-day period at two temperatures (10°C, 30°C). A 1-g amount of oil was added to a 1-cm layer of water covering salt marsh sediment and biodegradation was monitored with and without nutrient addition.…”

Section: Discussionmentioning

confidence: 99%

Laboratory evaluation of oil spill bioremediation products in salt and freshwater systems

Haines

Kleiner

McClellan

et al. 2005

J IND MICROBIOL BIOTECHNOL

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Ten oil spill bioremediation products were tested in the laboratory for their ability to enhance biodegradation of weathered Alaskan North Slope crude oil in both freshwater and saltwater media. The products included nutrients to stimulate inoculated microorganisms, nutrients plus an oil-degrading inoculum, nutrients plus compounds intended to stimulate oil-degrading activity, or other compounds intended to enhance microbial activity. The product tests were undertaken to evaluate significant modifications in the existing official United States Environmental Protection Agency (EPA) protocol used for qualifying commercial bioremediation agents for use in oil spills. The EPA protocol was modified to include defined formulas for the exposure waters (freshwater, saltwater), a positive control using a known inoculum and nutrients, two negative controls (one sterile, the other inoculated but nutrient-limited), and simplified oil chemical analysis. Three analysts conducted the product test independently in each type of exposure water in round-robin fashion. Statistical tests were performed on analyst variability, reproducibility, and repeatability, and the performance of the various products was quantified in both exposure media. Analysis of variance showed that the analyst error at each time-point was highly significant (P values ranged from 0.0001 to 0.008, depending on water type and oil fraction). In the saltwater tests, six products demonstrated various degrees of biodegradative activity against the alkane fraction of the crude oil and three degraded the aromatic hydrocarbons by >10%. In the freshwater tests, eight products caused >20% loss of alkane hydrocarbons, of which five degraded the alkanes by >50%. Only four products were able to degrade polycyclic aromatic hydrocarbons (PAHs) by >20%, one of which caused 88% removal. However, when the variability of the analysts was taken into consideration, only one of the ten products was found to yield significant percent removals of the PAH fraction and only in freshwater. Viable microorganism population analysis (most-probable-number method) was also performed on every sample by each operator to measure the changes in aromatic and alkane hydrocarbon-degrading organism numbers. In general, little evidence of significant growth of either alkane- or PAH-degraders occurred among any of the ten products in either the saltwater or freshwater testing.

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Section: Discussionmentioning

confidence: 99%

Laboratory evaluation of oil spill bioremediation products in salt and freshwater systems

Haines

Kleiner

McClellan

et al. 2005

J IND MICROBIOL BIOTECHNOL

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“…It seems unlikely that the presence of microorganisms associated with the organic matter would have been a significant factor in enhancing oil degradation because the hydrocarbon-degrading populations did not increase (Table 2) and there is little evidence that bioaugmentation promotes hydrocarbon degradation in soil having adequate nutrients (Neralla and Weaver, 1997;Riser-Roberts, 1992). Also, the soil had been incubated under favorable conditions for microbial activity 40 d before the plant materials were added, thus allowing time for populations to increase.…”

Section: Organic Bulking Agents For Enhancing Oil Bioremediation In Soilmentioning

confidence: 97%

Organic Bulking Agents for Enhancing Oil Bioremediation in Soil

ZhiZhou

Weaver

1998

Bioremediation Journal

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Soil contaminated with oil is bioremediated by optimizing conditions for microbial activity. Often the question arises about the benefits of bulking with organic materials to improve soil conditions to enhance degradation of the less biodegradable or less bioavailable components. An investigation was undertaken in the laboratory with the objective of measuring the influence of bulking with dried plant material, bermudagrass, and alfalfa on the degradation of oily sludge added to soil. The oily sludge was diluted 5050 on a weight basis with soil to achieve a final concentration of 100 g oil and grease kg' of final soil mixture. Bulking agents were added 40 d after dilution of the sludge and optimization of environmental conditions to allow time for the readily decomposable fraction to be degraded before amendment with bulking agents. Populations of heterotrophic microorganisms increased approximately ten times by 40 and 80 d after addition of bulking agents, but the numbers of hydrocarbon-degrading microorganisms did not significantly increase above the number in the nonbulked control. Bulking agents increased the quantity of total petroleum hydrocarbons degraded by approximately 20% during the first 40 d after being added. Disappearance of hydrocarbons for bulked treatments was much slower during the next 40 d, such that the total petroleum hydrocarbon content for both bulked and nonbulked treatments generally was not significantly different at the end. It appears that adding bulking agents may enhance the rate of decomposition of total petroleum hydrocarbons by stimulating the general heterotrophic population of microorganisms, but the influence may not be sustained to influence the extent of decomposition.

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“…However, large spills create a significant burden on the environment, and removal of oil by physical means prior to bioremedial treatment is recommended. Few statistically valid, peer reviewed studies have shown successful enhancement of oil degradation by adding inoculum to augment the resident microbial population [1,5,13,16,17]. Inoculation has had some success in soil treatment [5,16], but little success where active water movement occurs.…”

Section: Introductionmentioning

confidence: 98%

“…After 90 days, only one product enhanced oil degradation without added nutrients. With added nutrients, nine of ten products enhanced degradation of petroleum at 10°C [17]. Bachoon et al [3] examined microbial-community dynamics in salt marsh microcosms treated with oil and bioremediation products.…”

Section: Introductionmentioning

confidence: 98%

Protocol for laboratory testing of crude-oil bioremediation products in freshwater conditions

Haines

Koran

Holder

et al. 2003

J IND MICROBIOL BIOTECHNOL

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In 1993, the Environmental Protection Agency, National Risk Management Research Laboratory (EPA, NRMRL), with the National Environmental Technology Application Center (NETAC), developed a protocol for evaluation of bioremediation products in marine environments [18]. The marine protocol was adapted for application in freshwater environments by using a chemically defined medium and an oil-degrading consortium as a positive control. Four products were tested using the modified protocol: two with nutrients and an oleophilic component; one with nutrients, sorbent, and organisms; and one microbial stimulant. A separate experiment evaluated the use of HEPES and MOPSO buffers as replacements for phosphate buffer. The oleophilic nutrient products yielded oil degradation similar to the positive control, with an average alkane removal of 97.1+/-2.3% and an aromatic hydrocarbon removal of 64.8+/-1.2%. The positive control, which received inoculum plus nutrients, demonstrated alkane degradation of 98.9+/-0.1% and aromatic degradation of 52.9+/-0.1%. The sorbent-based product with inoculum failed to demonstrate oil degradation, while the microbial stimulant showed less oil degradation than the positive control. Replacement of phosphate buffer with other buffers had no significant effect on one product's performance. Differences in product performance were easily distinguishable using the protocol, and performance targets for alkane and aromatic hydrocarbon degradation are suggested.

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Inoculants and Biodegradation of Crude Oil Floating on Marsh Sediments

Cited by 16 publications

References 17 publications

Laboratory evaluation of oil spill bioremediation products in salt and freshwater systems

Laboratory evaluation of oil spill bioremediation products in salt and freshwater systems

Organic Bulking Agents for Enhancing Oil Bioremediation in Soil

Protocol for laboratory testing of crude-oil bioremediation products in freshwater conditions

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