New research led by The James Hutton Institute has demonstrated that microalgae could provide a sustainable alternative to conventional mineral fertilisers for malting barley production.
The study, published in Plant and Soil is the first original research paper to be published by a student on the BARIToNE programme. David Ashworth was one of the first cohort of students to undertake their PhD through the programme, a collaborative training partnership, which brings together 18 industry and seven academic partners to train the next generation of barley scientists and support innovation across the barley supply chain.
Microalgae can be cultivated using nutrients recovered from industrial waste streams and co-products, including distillery pot ale. This approach has the potential to create a more circular system for nutrient use while reducing dependence on mineral fertilisers, which contribute to greenhouse gas emissions due to the energy costs of production and transport and the nitrous oxide that is emitted when they are applied. Before investing in growing microalgae using industrial waste streams, its capacity as a replacement for mineral fertiliser to sustain barley production needed to be established.
Biological fertiliser
David said, “Our research explored whether microalgae could help reduce the agricultural sector’s reliance on synthetic mineral fertilisers while maintaining crop performance and grain quality.
“Across three separate glasshouse trials, barley grown with microalgae showed no significant differences from plants supplied with conventional mineral fertiliser across a range of growth and yield measures, including tiller number (the number of tillers, or side shoots, emerging from the main stem) and thousand grain weight (a measure of how large the grain is). Both treatments significantly outperformed unfertilised control plants.”
Building on these results, the team carried out a field-scale trial. Grain yields from plots treated with microalgal fertiliser were statistically equivalent to those receiving mineral fertiliser and significantly outperforming unfertilised controls.
Malt quality
Importantly for the Scotch whisky industry, assessment of malt quality also showed promising results. Measurements of hot water extract (the amount of fermentable sugars that can be extracted from the malt during mashing) and predicted spirit yield showed no significant differences between grain produced using microalgae and grain produced using conventional fertiliser, indicating that the alternative fertiliser could meet key industry quality requirements.
As part of the BARIToNE programme, Mr Ashworth undertook a placement with Chivas Brothers where he helped with their analytical pipelines, learned the techniques behind malt analysis and gained insight into how a distillery works. Stefan Masson, New Product Development, Innovation & Distilleries Support Manager, said, “This research is an important step towards the Scotch whisky industry’s ambitious net-zero goals and demonstrates how collaboration between industry and academia will be central to achieving them.
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“Given the significant carbon impact of inorganic mineral fertilisers, and current shortages linked to geopolitical instability, it is essential that potential alternatives are explored. David’s work has shown that algae could be a strong candidate for partially or fully replacing conventional fertilisers and has identified an opportunity to reuse distillery waste streams, helping to create a genuinely circular production cycle.”
While further field trials are needed to validate the findings across different environments and seasons, the researchers believe the results provide strong evidence that microalgae could play a role in future sustainable barley production systems and would also encourage an investigation into the plant and microbiome’s response to microalgae fertiliser.
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