Thermophilic microbial communities from a hot spring in western Thailand

Póster presentado en The 6th International Congress on Extremophiles, September 17 - 21, 2006 Brest France

The microbial community of a freshwater hot spring located in western Thailand was studied. Temperatures ranged from over 50 up to 57ºC. Within this mat yellow-, green-, and red-colored layers were analyzed using both culturing and molecular methods. In order to define the microbial community present in the mat as well as the microorganisms showing significant metabolic activity, the mat was analyzed using DNA- and RNA-based molecular techniques, respectively. Microbial community fingerprints obtained by Denaturing Gradient Gel Electrophoresis (DGGE), revealed the presence of a moderatedly diverse microbiota. These communities were largely constituted by thermophilic phototrophic microorganisms (63% of processed sequences). Over 40% of the screened sequences belong to the Cyanobacteria, and 23% of total sequences were related to the photosynthetic bacterium Roseiflexus and other Chloroflexi. Most Cyanobacteria were closely related to the genus Thermosynechococcus. Other non-photosynthetic microorganisms detected in the mat were Bacteroidetes (14%), members of the Candidate Division OP10 (15%), Actinobacteria (5%), and Planktomycetes (2%). Archaea or Eukarya were not detected. Among the cultured microorganisms, representatives of the genus Meiothermus (Deinococcus-Thermus group) was the most commonly cultured bacteria. Comparative microbial community fingerprints showed that most microorganisms present in the mat (from DNA-based molecular analysis) showed metabolical activity (from RNA-based molecular analysis) in the sampled mat suggesting that most of its microbial components contribute to its development. These results show the presence of a thermophilic bacterial community basing its development in the active role of the photosynthetic prokaryotic members which constitute the majority of the community.

Peer reviewed