How a cow’s digestive system could revolutionise renewable energy

A group of scientists believe that the key to effective biomass conversion lies in the stomachs of cows and elephants, with new research revealing that mimicking the digestive systems of these animals could create a streamlined and cost-effective biomass generator.

Researchers at the Agricultural Centre of Sustainable Energy Systems (ACSES) at Harper Adams University are examining the anaerobic fungi that herbivores use to convert plant-based foods into energy as a way to revolutionise biomass technology.

ACSES leader Professor Theodorou said: “The objective of our work was to find an alternative, more straight-forward platform, mimicking the conversion of plant biomass to useful products in nature.

“In our work so far, we have identified hundreds of enzymes from the gut fungi, which have commercial biotechnology potential. It is because these fungi are able to survive in such a highly-competitive microbial ecosystem, where a myriad of protagonists seek to degrade plant biomass, that we believe they are so effective at their job.

“We have so far shown that some of these enzymes are substantially better than the current solution at converting plant biomass to sugars. We need to invest more resources to study this group of relatively unknown microorganisms. They may hold the key to the renewable technology of effective biomass conversion. Their full potential must be explored and exploited.”


Currently, genetically-modified enzymes from fungi such as Trichoderma and Aspergillus are used to digest plant-based biomass. However, both the pre-treatment of these enzymes and the fermentation methods to produce bio-ethanol are costly.

Theodorou – who has been researching these enzymes for more than 25 years – believes that mimicking the enzymes found in herbivores would allow renewable energy generation to bypass the extensive costs of pre-treatment.

Researchers have previously claimed that using cow manure could provide up to 3% of America’s electricity needs, while simultaneously slashing greenhouse gas emissions. Closer to home, more than 430 households in Northern Ireland have been provided with heat and electricity by the poo from 600 cows by the Greenhill Dairy Farm Biogas farm.

Elephant in the room

Much like the majority of renewable generation capabilities, biomass is suffering from the lack of enablers in the UK’s political environment. While waste management giants such as Veolia continue to expand in the sector, the removal of tax exemptions for renewable power generators has created a less stable environment for growth.

Drax has been driving a transition into the biomass sector, with two of six units converted to run on biomass. Research commissioned by the firm found that opening up future contracts for difference (CfD) to a wider array of technologies could save consumers around £2bn.

Biomass conversion, which is not eligible for the next round of CfDs, would cost £30/MWh less than the whole system cost for offshore wind – which is expected to be the main recipient of subsidies.

Matt Mace

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