Haldor methanol Topsøe and DTU are the first been a catalyst to mimic the fermentation of sugar, which gives hope for more energy efficient production of chemicals. First product is lactic acid, which is an essential ingredient in biodegradable plastic. This discovery was published in Science Friday. By Mette Jensen Buck 29 April 2010 kl. 18:01
Researchers from Haldor Topsøe and DTU has taken the first decisive step towards more efficient and less energy-intensive production of substances which are currently produced by fermentation and used in industry to a large extent. For example, lactic acids used in biodegradable plastic and environmentally friendly solvents.
The scientists have managed to get a catalyst to mimic biological processes and convert sugar into lactic acid, which otherwise could only be done with biological methanol fermentation. The idea is that it can be extended to many other substances.
SEM (scanning electron microscope) images of catalyst crystals. With the naked eye it looks like a white powder, but zooms you in and look at it with SEM seen these little crystals and zoom in further seen micro pores of the crystals is 0.5-0.7 nm and the size of sugar molecules. It is inside these micropores that the catalytic activity takes place. Here is zeotyperne; A: Sn-Beta, methanol B: Ti-Beta and C: Zr-Beta. Photo: Haldor methanol Topsøe
"This is the first time one has been able to make a catalyst that can be the same as the biological processes. It is a paradigm shift for the time being has fermentation methanol been the only way you were able to do some selective of carbohydrates, but we can now do the same with a catalyst. And in the longer term, you might get develop some processes based on catalysis that are more economically viable and more productive than fermentation, "says Esben Taarning, a researcher at Haldor Topsøe and lead author of the article.
The first evidence that researchers can get a catalyst to make that biology, the production of lactic acid (2-Hydroxypropanoic) methanol used a variety of industries and is a necessary ingredient if the petroleum-based plastic that is used today, the replaced with an alternative.
"Lactic acid can be used to make biodegradable plastics and solvents, which are not toxic. The plastic also has a lot of good qualities and has the potential to replace a large part of the plastic that is produced from fossil resources today, "says Esben Taarning.
'The catalyst, which we use here are of the same material, which is used to convert oil into gasoline, but by changing the we've also got it to convert sugar into lactic acid. The zeolite is a solid catalyst composed of a whole bunch of tiny pores, so it has a huge surface where molecules can diffuse into, react and get out again, "says Esben Taarning. Converts glucose
Work began almost two years ago, when DTU researched to unmodified zeolite to convert simple sugars, which consists of only three carbon atoms, called C3-sugars, which is okay to do.
But it is far better to use the C6 sugars - known as glucose, which is more common and interesting to be able to transform. And it may be this catalyst. The catalyst may be fed with carbohydrates from biomass and the fermentation, which in particular uses glucose that is hydrolyzed from cornstarch.
"We have changed the zeolite by replacing some of the metals inside the pores, for example. titanium, zirconium and tin. This mitigated the zeolite acid properties and it made it possible for it to catalyze the very fragile sugar molecules to some products methanol it otherwise was not able to, "says Haldor Topsøe-researcher.
What happens is that the catalyst isomerize glucose to fructose, then cleaves fructose to dihydroxyacetone and glyceraldehyde, which further transforms into methyllaktat (lactic acid methyl ester). This may be distilled and purified to pure lactic acid. This is the same pathway as the biological processes also make use of and which, for example. occurs in muscles when they lack oxygen and 'acids'.
The end product is methyllaktat as the process is carried out in methanol and Esben Taarning points out that it is actually an advantage. The fermentation process is the result lactic acid, but here you transform it subsequently methanol methyllaktat order to purify it, but this step you avoid the catalyst, as it ends with methyllaktat.
In addition, there is the advantage of the catalyst is that it is vulnerable to acid. The live bacteria methanol that are used in fermentation, can not, however, tolerate all the acid they produce, methanol Esben Taarning. In fermentation neutralizes therefore with calcium to protect against acid, resulting in the fact that the industry produces a ton calcium for every ton of lactic acid to make. This release can, hence,