Ecological and enzymatic responses to petroleum contamination

Abstract

The changes in microbial ecology interpreted from taxonomic and functional genes and biological functions represented by urease and dehydrogenase activities were monitored in soil contaminated with different petroleum hydrocarbons including crude oil, diesel, n-hexadecane and poly-aromatic hydrocarbons (PAHs). It was shown that the presence of n-hexadecane stimulated the activity of indigenous microorganisms, especially alkane degrading bacteria, and led to over 20% degradation of n-hexadecane within one month. No obvious degradation of the other three types of petroleum hydrocarbons was observed. The stimulation effect was most marked in the soil spiked with a medium concentration (2500 mg kg(-1) dry soil) of n-hexadecane. However, the presence of PAHs completely inhibited the previously-mentioned bioactivities of the soil. The content of PAH degrading bacteria, however, increased more than 10-fold, indicating the selection effect of PAHs on soil bacteria. The impacts of diesel and crude oil on the microbial ecology and biological functions varied significantly with their concentration. The disclosure of the ecological and enzymatic responses could be helpful in soil bioremediation.

Activity and functional diversity of microbial communities in long-term hydrocarbon and heavy metal contaminated soils

“…Soil I, which was the least contaminated one, had the lowest activities of urease and alkaline phosphatase. Contrary to some other studies (Gianfreda et al 2005, Turgay et al 2010, Wu et al 2014) no correlation was observed between urease activity and the level of PAHs. Thus, the variations in enzyme activities between soil samples showed that in tested soils pollution inputs have specifi c site effects, which may be a result of lower sensitivity of local microbial communities to PAHs and heavy metals.…”

“…Both the most contaminated (II) and the least contaminated (I) soils exhibited a noticeable separation from the two other soils in the fi rst principal component (PC1), which explained 78.5% of the variation in the data. The reason for these fi ndings may be the selection and adaptation of microorganisms to the pollutants, which cause a lack of species or strains capable to degrade a variety of carbon sources (Wu et al 2014). The second PCA analysis was carried out for physicochemical data, Σ16PAHs concentrations and enzymatic activities (Fig 2B).…”

Response of Avena sativa, microorganisms and enzymes to contamination of soil with diesel oil

“…Their RS index nearly approached the value of one, and ranged from 0.91-0.95. The varied response of microorganisms to the tested contamination was associated with their succession (Vázquez et al 2013) resulting from the death of sensitive microorganisms, and the multiplication of the resistant ones (Wu et al 2014). Changes to the multiplication of microorganisms in the soil contaminated with diesel oil may result from the fact that hydrocarbons, as the chemical compounds with a various degree of bioresistance, are degraded at different rates, and they have an effect on the soil microbiota in consequence (Semrany et al 2012).…”

Response of microbial communities to oil spill in the Gulf of Mexico: A review

“…Some other intense oil spill examples are the tanker collision in the Mumbai coast and the oil spill in Montora (Sakthipriya et al, 2015) Microbial communities are known to control most major processes that occur in the marine environment (Karl, 2007). One important function and process is biodegradation of contaminants and nutrient recycling that helps to ensure an effective and efficient ecosystem (Wu et al, 2014). Hydrocarbon degradation by microorganisms has received much consideration because of its unhazardous, inflammability, extensive and environmentally friendly state when likened to other orthodox methods (Sakthipriya et al, 2015).…”