Tweaking Mother Nature's chemistry box
Natural enzymes are very clever molecular machines. They are the catalyst for many of nature's chemical transformations. And the conditions they need to perform their task are rather precisely defined. There is a need to study enzymes, in order to adapt them as a means to harness their power for industrial scale chemical processes. For example enzymes included in washing machine detergent contribute to helping making the laundry clean. But they need to be adapted to survive the warm laundry conditions.
This is precisely what the recently completed Oxygreen project, funded by the EU, aimed to do. "Enzymes are everywhere; even in our own body," says project coordinator professor Marco Fraaije, group leader of the research division of molecular enzymology at the University of Groningen, the Netherlands. "It's enzymes that turn our food into energy we can use."
The three enzymes under study in the project were: Cytochrome P450 monooxygenases, Baeyer-Villiger monooxygenases, and non-heme iron dioxygenases. All three can be used for performing refined oxidation reactions. And they attract more and more attention for their use in chemical processes that are of interest to the chemical industry. Currently, these oxidation processes are very crude and difficult to control. They require very high temperatures and produce a lot of waste. An enzyme which could do the same thing at lower temperature and without producing as much waste on an industrial scale would be welcome.
So are the enzymes chosen by the project scientists really were the best ones for the task? Other European scientists think so. "Well, it's a good idea to choose enzymes which use oxygen, because oxygen is readily available everywhere, clean, and once the enzyme has performed it's task you can even use it as an animal feed," says Wolfgang Kroutil, professor of enzymology at the Institute of organic and bioorganic chemistry of the Karl Fränzens University in Graz, Austria. "It's very simple to recycle in this fashion. Furthermore it's exactly these three enzymes which can be highly specific; they produce the desired substance, and nothing else. No waste products, and no pollution. Traditional chemistry isn't capable of doing that," he tells youris.com.
Other experts concurs, but with some caveat. "I wonder if these three enzymes can be mass produced cheaply," says Gustav Kolstad, senior researcher at the department of biotechnology of the University of Aas in Norway. "On the other hand, if the result of the biochemical reaction is valuable enough, for instance an expensive pharmaceutical, then I'm sure the industry will gladly pay the price," he tells youris.com.
Meanwhile the the enzyme engineering project appears to be a success. For example, a patent is pending on a process developed by one of the project partners to make a plastic using polymer precursors produced out of agricultural waste. This prompt industry adoption of the project results is encouraging. Marco Fraaije concludes: "The industry believes in it. And they just don't take any risks."