The relationship between the microbial activity of the autochthonous microorganisms of pristine and contaminated soils and their potential for the degradation of mineral oil hydrocarbons

Abstract

The microbial activity of pristine and contaminated soils was investigated by measuring the following parameters: glucose induced respiration, dimethylsulphoxide reduction and the hydrolysis of fluorescein diacetate. The viable counts were determined by the plate count method. The ability of the autochthonous microorganisms of the investigated soils to degrade diesel fuel was determined in a closed system on the basis of the oxygen consumption and by direct measurements of the hydrocarbon concentrations. As expected, compost showed the highest microbial activity with regard to all three parameters, followed by the grassland and the arable soil samples which were also found to have high activity. However, soils that had been exposed to mineral oil for a long period of time showed significantly lower values. Microorganisms from contaminated sites had a high degradation potential; few pristine soils reached similar turnover rates. The investigations showed that the level of the degradation of diesel fuel in pristine soils correlated with their microbial activity, but this correlation was not found in the investigated contaminated soils.

Characterization of Hydrocarbon-Degrading Microbial Populations in Contaminated and Pristine Alpine Soils

“…However, microbial counts did not correlate significantly with biological activities (with some exceptions for FDA hydrolysis). Similar results have been described previously (32). Biological activities were higher in pristine than in oil-contaminated soils, while microbial numbers were similar in pristine and contaminated soils (32).…”

“…Similar results have been described previously (32). Biological activities were higher in pristine than in oil-contaminated soils, while microbial numbers were similar in pristine and contaminated soils (32). Positive correlations between microbial counts and soil biological activities have been reported mainly for bioremediation studies after the biostimulation of soil microorganisms (11,31,47).…”

“…In a study of the impact of hydrocarbons on soil enzyme activities, the presence of diesel oil resulted in significantly increased FDA hydrolysis and lipase activity compared with those in uncontaminated controls (28). However, other authors found distinctly lower rates of FDA hydrolysis in oil-contaminated soils than in pristine soils (32). Soil lipase activity is a valuable tool to monitor oil biodegradation in freshly diesel oil-contaminated soils (30), most probably due to a high content of available aliphatic compounds.…”

Bioremediation of crude oil-contaminated soil: Comparison of different biostimulation and bioaugmentation treatments

“…Colorless fluorescein diacetate is hydrolyzed by both free and membrane bound enzymes, releasing a colored end product fluorescein which can be measured by spectrophotometry. However, microbial counts did not always correlate significantly with biological activities [24]. In the case of stored bacteria, longterm dormancy or starvation can lead to low enzymatic activity, even though these cells are viable.…”

Determination of substrate utilization patterns of soil microbial communities: An approach to assess population changes after hydrocarbon pollution

“…Long-term incubation of polluted and unpolluted soil samples was carried out in a Sapromat D 12 (Voith Ltd., Heidenheim, Germany) under aerobic conditions using 2 or 3 replicates [15]. Mineral oil contamination of a pristine soil was simulated by the addition of 1.2% spindle oil (boiling range 320-400°C deparaffinized).…”