Hot springs are home to a large number of unique thermophilic organisms that can live at temperatures above 50 degrees Celsius, including due to the heat resistance of their proteins. Some thermophiles are used for biotechnological purposes. For instance, the enzyme of Taq DNA polymerase, which is used to conduct PCR analysis, was isolated from the bacterium Thermus aquaticus, which was discovered in the thermal springs of Yellowstone National Park. However, microbial communities in most hot springs remain unexplored.
A breakthrough has been achieved by scientists from the Federal Research Centre “Fundamentals of Biotechnology” of the Russian Academy of Sciences, who have discovered a new species of bacteria in a hydrothermal spring in North Ossetia. The microorganism, named Tenuifilum osseticum by the authors, looks like a thin rod, which is 0.13–0.2 micrometers thick and 5–10 micrometers long.
Although this species lives in freshwater hot springs at 55 degrees Celsius, the authors experimentally showed that it can grow at temperatures from 30 to 55 degrees Celsius and a salinity of up to 4%. The microorganism does not need oxygen: instead of breathing, it uses fermentation to obtain organic substances. For instance, Tenuifilum osseticum ferments simple sugars (glucose, maltose, etc.), polysaccharides (starch, xylan, laminarin) and proteins (peptone, gelatin, casein), converting them into acetic acid, hydrogen and carbon dioxide.
The researchers also deciphered the genome sequence of Tenuifilum osseticum and found a number of genes responsible for the synthesis of enzymes involved in metabolism. These enzymes allow the microorganism to use sugars and proteins in its activity. However, the authors could not find any genes responsible for the formation of flagella.
“The new bacterium has a number of common features with a related species we described earlier, Tenuifilum thalassicum. They are both thermophilic and shaped like thin rods, and they both live in oxygen-free conditions and ferment simple sugars, polysaccharides and proteins. However, Tenuifilum osseticum grows in a narrower range of temperatures and a wider range of salinity. The latter fact is especially surprising, as the new species was isolated from a freshwater source, whereas its relative lives in marine hydrothermal vents,” Olga Podosokorskaya, candidate of biological sciences, is quoted as saying by the Russian Science Foundation.
