Distribution of alkane-degrading bacterial communities in soils from King George Island, Maritime Antarctic

The structure of alkane-degrading bacterial communities, which are present in both the hydrocarbon-polluted and pristine soils of King George Island in Maritime Antarctic, was studied using molecular methods. Polymerase Chain Reaction (PCR) amplifications of the alkane monooxygenase AlkB-coding genes, followed by Restriction Fragment Length Polymorphism (PCR-RFLP) and Denaturing Gradient Gel Electrophoresis (PCR-DGGE) analyses, revealed the widespread presence and complex diversity of alkane-utilizing bacteria in these soils. The resulting dendrograms and Canonical Correspondence Analyses (CCA) of PCR-RFLP and PCR-DGGE patterns showed that the characteristics of the different soils, such as physicochemical properties, soil type and/or hydrocarbon contamination levels, affect the distribution of alkane-degrading bacteria. Sequencing of 20 DGGE bands revealed the presence in Antarctic soils of alkane monooxygenases with low similarity (61-91%) compared to those previously described in Gram-positive bacteria, such as Mycobacterium, Gordonia, Rhodococcus and Aeromicrobium. The high diversity of alkB genes in the soils of King George Island suggests the potential for oil pollutant degradation. (C) 2012 Elsevier Masson SAS. All rights reserved.