Professor Michael Theodorou, leader of the Agricultural Centre of Sustainable Energy Systems (ACSES) at Harper Adams is one of the authors of a new paper published online in the journal Science on 18th February. The paper describes the potential benefits of using anaerobic fungi, microorganisms that live in the gut of herbivores, in the production of chemicals and renewable energy from plant biomass.
Currently, genetically-modified enzymes from aerobic fungi, such as Trichoderma and Aspergillus, are being used to digest plant biomass, followed by the fermentation of released sugars by yeasts to produce products such as bio-ethanol.
“This strategy is complex and not cost-effective because it requires chemical pre-treatments to remove lignin from plant biomass, prior to the two-stage microbial process” 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 report we show that enzymes from anaerobic fungi native to the gut of herbivores are substantially better than genetically-modified aerobic fungal enzymes at converting plant biomass to constituent sugars.”
Professor Theodorou added that anaerobic fungi are found in the digestive tract of wild and domesticated herbivores as wide ranging as elephants and cattle. These microorganisms convert plant biomass to sugars which are further processed as energy sources for the animal. Moreover, the gut fungi are able to achieve plant biomass conversion effectively and without the need for chemical pre-treatment. It is not only the number of active enzymes in these fungi that are important but also how they are controlled and architecturally aligned to their substrates, which makes them exceptionally effective in breaking down the structural components of plant biomass.
The team of scientists, including Michelle O’Malley and her team from the University of California, Santa Barbara, managed to identify hundreds of enzymes from anaerobic fungi with 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 the scientists believe they are so effective at their job.
More resources are needed to study these relatively unknown microorganisms but they may hold the key to the renewable technology of effective biomass conversion.
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