What can bread, tub of ice cream and a box of washing powder have in common? The answer can be found in their composition: these three products use enzymes originating from psychrophiles. That is to say, organisms that can thrive at very low temperatures. For several years now, they have been the subject of in-depth research owing to their numerous properties and their vast field of application. Georges Feller, head of the Laboratory of Biochemistry (Centre for Protein Engineering) at ULg, has just published an article (1) in which he provides a list of the latest advances in the subject. Whether they are used in our mass consumer products or in fundamental research, psychrophiles are far more present than we might imagine.    

They aren’t afraid of the snow, the extreme cold or polar temperatures. Even better: that is where they feel perfectly at home. They can be found in every fridge and freezer worldwide. But it is in Antarctica and the Arctic that they have officially decided to take up residence. Generally invisible to the naked eye, they can nevertheless take the form of fish or algae. They can also be found in our tubs of ice cream, boxes of washing powder, and even cosmetic products.

“They” are psychrophiles. This difficult-to-pronounce name describes organisms capable of living in very cold weather conditions.  The complete opposite to their “cousins”, thermophiles, which require high temperatures to exist and multiply.

For a long time, the latter monopolised the attention of the majority of laboratories. Scientists believed that they were the main source of innovation in terms of biotechnology. But the trend has gradually been reversed. Specialists started to observe psychrophiles more closely and thus discovered that these “cold-lovers” were actually highly abundant and diversified, and that studying them could lead to a multitude of applications. “All that thanks to NASA”, says Georges Feller, head of the Laboratory of Biochemistry (Centre for Engineering Proteins) at the University of Liège. “This American governmental agency has financed many programmes within the framework of developing exobiology, i.e. the study of the appearance of certain life forms on other planets. If these life forms exist, they develop in either very hot environments or in very cold ones. For instance, the substratum on Mars is frozen.  As a result, this has stimulated research in this domain.”

Georges Feller is well acquainted with psychrophiles. He has been studying them for more than 20 years. He and his team have been on approximately 15 expeditions to Antarctica to collect samples. Their intention isn’t really to find out whether these organisms are present on Mars, Jupiter or Pluto, but rather to study the way in which certain molecules can be used in concrete applications. “We are interested in the enzymes that are similar to the enzymes we already know about. Our intention is to compare them and understand why the former are capable of functioning at below zero temperatures so that we can perhaps use them to replace the latter”, he explains. In collaboration with Dr. Rosa Margesin, professor of microbiology at the University of Innsbruck (Austria), he has just published an article in which he reviews the multiple uses of these microorganisms.

(1) Georges Feller et Rosa Margesin, « Polar microorganisms and biotechnology » in Polar Microbiology: Life in a deep freeze, Washington, ASM Press, 2012.