Le site de vulgarisation scientifique de l’Université de Liège. ULg, Université de Liège

Psychrophiles for all
3/9/12

More ecological, more economical

A rather extensive list. For instance, industry has turned out to be particularly fond of psychrophiles. And with good reason: they have three significant advantages. First of all, they are active not only at low temperatures but also at an ambient temperature. Subsequently, products that contain them no longer need to be heated, either during the manufacturing process or in their domestic use. And because they are very active, fewer are needed for the preparation, therefore leading to savings. Finally, they are thermolabile. That is, they lose their properties when the temperature rises. In other words, it is simply a question of increasing the temperature slightly to neutralise them.

The most popular example is undoubtedly that of “low-temperature” washing powders. If you open a tub of the well-known brand that has made this concept its warhorse, you will perhaps notice tiny grey granules in this powder. In reality, these small pearls contain protease, a subtilisin which is the most abundantly produced industrial enzyme in the world. Subtilisin acts on stains a bit like a glutton that doesn’t need to be heated to be efficient. As a matter of interest, it is Georges Feller and some of his colleagues who are behind this concept of powders that can work at low temperatures. A concept they initially discovered in the 1990s but because it wasn’t protected by a patent, it ended up being massively exploited by industry…

A  “beginner’s mistake” that was never committed again, when the team from Liège worked in collaboration with the Belgian firm Puratos, specialising in the preparation of raw materials for bakers and confectioners. The aim was to succeed in isolating xylanase, an enzyme originating from the Antarctic bacteria P. haloplanktis to help improve the quality of bread. “Xylanase cuts bread flour into small pieces”, Georges Feller explains. “This allows the dough to rise far more, to be lighter and softer. And as it is unstable during cooking, any possible residual effects then disappear.”

Another food application, for which the laboratory of biochemistry has also registered a patent, is lactase. An enzyme that once again originates from an Antarctic bacterium, which should be particularly appreciated by people who are lactose-intolerant  (approximately 75% of the population worldwide suffers from this intolerance!). Poudre lessiveAfter a certain age, this sugar, which is mainly found in dairy products, isn’t digested properly anymore (i.e., it is cut in two) by the body, thus leading to digestive problems. As for lactase, it can hydrolyse (or split) lactose into glucose and galactose – sugars which are far easier to assimilate – as soon as milk is stored in cold conditions. This cold enzyme is also used in the manufacturing of tagatose (read the article: The sugar-producing enzyme), a sugar commercialised by the Belgian company Nutrilab, that is used as a natural sweetener while also helping to prevent diabetic reactions.

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