Biosprit from the goat's belly

Herbivores' intestinal fungi possess hundreds of enzymes for biofuel production

Goat and Co intestine mushrooms have an astonishingly large arsenic of enzymes for degrading plant material. © University of California, Santa Barbara
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New opportunity for bio-fuels? US researchers have discovered in the faeces of goats, sheep and other herbivores unexpectedly effective helper for biofuel production. Because the microscopically small intestine mushrooms of these animals possess an astonishingly large arsenal of enzymes with which they can decompose and convert even hard, woody plant waste effectively, as the researchers in the journal "Science" report.

Fuels and basic chemical building blocks from renewable plant raw materials would be an environmentally friendly alternative to petroleum as a base material - theoretically. But in practice it hapers with it. Because ecologically sensible this would be only with the use of plant waste and woody plant parts.

Found in the feces of goat and co

But these are so far too stable to be enzymatically converted into biodiesel and CO in fermenters. As a result, specially grown energy crops such as rapeseed are used instead, which rival food cultivation and also promote over-fertilization of the land. However, Kevin Solomon of the University of California at Santa Barbara and his colleagues may have found a solution to this dilemma.

Investigating the feces of goats, sheep and horses for potentially beneficial microbes, the researchers came across three promising representatives of tiny fungi living in the intestine of the animals. "These fungi make up only about eight percent of the intestinal flora, but decompose up to 50 percent of the intake of plant food, " explain Solomon and his colleagues.

The intestinal fungi form fabulous processes, at the ends of which they release the degrading enzymes. © University of California, Santa Barbara

A whole arsenal of enzymes

Closer examination of these intestinal fungi has revealed that they produce hundreds of enzymes that can deplete lignocellulose and other highly resistant plant components. "Nature has optimized these fungi to have the world's largest repertoire of biomass-degrading enzymes, " says study director Michelle O'Malley of the University of California. display

The big advantage: The fungi can not only break down grass, woody parts and other robust plant wastes with these enzymes, they are also extremely adaptable. No matter what the researchers fed to the fungal cultures, cellulose, hemicellulose, lignin, glucose, or the wood ingredient xylan, the fungi simply rearranged their enzyme production - within a very short time.

More effective production of bio-fuel

For the production of biofuels and chemical raw materials from plant wastes, the enzyme arsenal of these mushrooms could prove to be a real treasure chest. Because industrial processes can only decompose woody parts of plants or grass and convert them to sugars or biodiesel, if they have been previously elaborately pretreated at high temperatures and with the addition of chemicals.

So far, especially so-called energy crops such as oilseed rape, sugar cane or palm oil for biodiesel and co. Are grown. Myrabella / CC-by-sa 4.0

And even then, some of the components turn out to be unusable for the hitherto commercially used and usually laboriously modified enzymes. In contrast, the goat and goat's intestines, thanks to their enormous enzyme range, can easily do this without major modifications. They could therefore make the production of biodiesel and co much more effective and environmentally friendly.

"Because these guts have more tools to convert biomass into fuels, they could work faster and work with a wider variety of plant materials, " says O'Malley. "This opens up many opportunities for the biofuel industry." (Science, 2016; doi: 10.1126 / science.aad1431)

(DOE / Pacific Northwest National Laboratory, 22.02.2016 - NPO)