Metagenomic Analyses of Genes Encoding Key Enzymes for Hydrocarbon Biodegradation in Subantarctic Coastal Sediments

LOVISO, C.; GUIBERT, L.; MARCOS, M.; LOZADA, M.; DIONISI, H.

Trivandrun

Congreso; New Horizons in Biotechnology; 2011

National Institute for Interdisciplinary Science and Technology- CSIR

With the aim of gaining insight into marine bacterial populations with hydrocarbon biodegradation potential in a chronically-polluted Subantarctic coastal environment, we characterized intertidal sediment samples from Ushuaia Bay (South Patagonia, Argentina) using culture-independent methods. We found a high diversity of gene variants encoding aromatic ring-hydroxylating dioxygenases and alkane monooxygenases: 22 and 30, respectively. The abundance of three novel dioxygenase genes previously identified in sediments from Ushuaia (B, C and D), as measured by quantitative PCR (qPCR), were comparable to or higher than archetypical nahAc, phnAc and phnA1 genes during a six-year time span. In addition, we constructed a metagenomic fosmid library from a representative sample of this site covering 2 Gbases of genetic information from the microbial community. The screening of this library is being carried out using primers targeting different variants of oxygenase genes. Preliminary results suggest the presence of clones carrying the novel gene variant D in the library at a frequency similar to the one estimated in the sediments by qPCR. The analysis of the 40 Kb inserts of clones containing oxygenase genes will provide valuable information about the biodegradation pathways used by ecologically relevant bacterial populations in Subantarctic marine environments.