Evaluation of alkane biodegradation potential of environmental samples by competitive PCR

摘要

A molecular method for evaluation of the biodegradation potential of microflorae of polluted sites was tested focusing on the detection of the alkB gene, encoding alkane hydroxylase which catalyses the hydroxylation of n-alkanes. AlkB-related genes are found in many bacterial genera, and often have reduced sequence similarities. Therefore, four different primer pairs were designed, based on classification of available partial sequences of alkane hydroxylase genes. These primers allowed amplification of alkB-related genes in 14 out of 15 tested alkane-degrading strains or microcosms. In addition, competitive PER experiments showed that alkB genes could be correctly quantified in the tested strains. AlkB genes were also quantified in pristine or contaminated water samples and compared to the corresponding n-heptane degradation rate. Results show that alkB gene copy numbers follow the same tendency as degradation rates and suggest the suitability of this method for a rapid evaluation of hydrocarbon degradation capacities of environmental samples.