Bioremediation of hydrocarbon degradation in petroleum-polluted soil is carried out by various microorganisms.  In the article, collaborating researchers from Xi’an University in China and The Ohio State University argue that little information is available for the relationships between hydrocarbon degradation rates in petroleum-contaminated soil and microbial population and activity in laboratory assay.

In their microcosm study, the researchers determined the degradation rate and efficiency of total petroleum hydrocarbons (TPH), alkanes, and polycyclic aromatic hydrocarbons (PAH) in a petroleum-contaminated soil using an infrared photometer oil content analyzer and a gas chromatography mass spectrometry (GC-MS).

The study also involved the enumeration of the populations of TPH, alkane, and PAH degraders were by a modified most probable number (MPN) procedure, and the hydrocarbon degrading activities of these degraders were determined by the Biolog (MT2) MicroPlates assay.

The results of their investigation showed linear correlations between the TPH and alkane degradation rates and the population and activity increases of TPH and alkane degraders, but no correlation was observed between the PAH degradation rates and the PAH population and activity increases.  Petroleum hydrocarbon degrading microbial population measured by MPN was significantly correlated with metabolic activity in the Biolog assay.  The results suggest that the MPN procedure and the Biolog assay are efficient methods for assessing the rates of TPH and alkane, but not PAH, bioremediation in oil-contaminated soil in laboratory.