Ciencia Colombia , Bogotá D.C., Martes, 12 de enero de 2016 a las 10:43

Bacteria and fungi thrive in extreme environments in Colombia

Although seemingly unthinkable there are beings on Earth capable of surviving temperatures above 45º C (113º F) and known as thermophiles, which are a subgroup of the extremophiles (microorganisms which subsist in extreme environments)

UN/DICYT Among the extremophiles is Anisakis simplex a worm that can resist the radioactivity of Chernobyl (Ukraine); Chromohalobacter beijerinckii, a bacteria capable of enduring the high salt concentration of the Dead Sea and the tardigrades which survive in extremely dry environments in the Desert of Atacama, in Chile.

 

The discovery of extremophiles on Earth suggests there could be analogous organisms on planets such as Mars; in fact they could be the only ones capable of living on the Martian soil which in the summer has temperatures in the range of -20º C (-4º F) and in winter -100º C (-148º F). Furthermore they would also have to endure high saline conditions which allow water to remain liquid in such low temperatures.

 

There are also extremophiles in Colombia; the Universidad Nacional de Colombia (UNal) Faculty of Sciences Astrobiology Research Group is a pioneer in this area and in discovering them.

 

For instance, 45 minutes from Bogotá, on the hot springs of Santa Mónica, near the municipality of Choachí (Province of Cundinamarca) researchers discovered Bacillus and Mycrobacterium bacteria which can endure temperatures of up to 55 ºC (131 ºF) as well as halophile fungi which can withstand high salinity levels.

 

UNal biologist and group coordinator María Angélica Leal says that the conventional conditions for organisms to thrive on earth are: 37º C (98.6º F), pH of 7, salinity between 0.9% and 3%, and a high pressure atmosphere; therefore any modification to these patterns are considered extreme.

 

Taking into account that Colombia has areas between 0 and 4,000 m (13,123 ft) high and temperatures below -5.6º C (21.9º F) in Andean tundras and glaciers and extreme temperatures in the range of 40º C (104º F); the members of the group began a search for extremophiles in Colombia.

 

Heat resistant

 

They first traveled to the hot springs of Choachí and took samples of the water. Then they placed them on petri dishes with traditional growth media enriched with hot spring water and temperatures of 55º C (131º F). They discovered five strains of thermophile bacteria and two consortiums (association between two or more microorganisms which produce metabolites).

 

“The microorganisms in the samples had slow growth as it took them between 8 and 15 days to develop while a normal bacterium takes only 24 hours. This situation hindered the process of obtaining pure strains but was a good indicator of the possible differences between the functions of these organisms (physiology) and the amount of chemical reactions which transform nutrient molecules which will later be used for synthesizing extremophile structural components (metabolism),” said Leal.

 

Then they began a molecular identification, which is a difficult task because bacteria have external layers known as exopolysaccharides which are very thick and make extracting the genetic material hard; however after overcoming this issue they extracted the DNA and performed biological data analyses and identified the bacteria as from the genus Bacillus and Mycrobacterium.

 

Fungi with salt please

 

Encouraged by these results, the group decided to visit the Nemocón salt mine to take triplicate samples of the soil, walls and water. Then they tried to release and isolate the microorganisms within the salt. Afterwards they carried out tests with different salinity levels (5, 10, 15, and 30%) at room temperature and in complete darkness. Seawater, for example has 3.5% salinity.

 

The researchers discovered two types of halophile fungi; a yeast of the Saccharomyces genus which can ferment multiple carbohydrates and can endure salinity levels of up to 15% and Penicillium, a genus which includes more than 300 species, including Penicillium chrysogenum, from where penicillium is obtained, which tolerated up to 30% salinity.

 

Furthermore Leal said that these types of fungi could also have biotechnological applications, for instance in improving the quality of impoverished or eroded soils due to excessive use as they endure high stress levels.

 

For the research group, extremophile research is very important for astrobiology, a science which tries to explain the origins, evolution and future life in the universe, as the existence of microorganisms in extreme environments has extended what was believed were the essential requirements for life development.