Use of algae towards sustainable fertiliser supply detailed in new research

Research into algae that could support the sustainable production of biofertilisers has been published by Sheffield researchers.

Research into the many uses of algae is taking place across the Department of Chemical and Biological Engineering.

Agricultural challenges such as the sustainable supply of biofertilisers could be solved by new research showing how different strains of algae from a similar habitat have different capacities to absorb key ingredients, potentially from wastewaters.

Current chemical fertilisers often used in the agricultural industry are not all absorbed by the plants due to the quantities used, leading to some of them being washed away into water bodies such as lakes when it rains. This then encourages algae to grow, which can cause other plant life in lakes to die due to a lack of sunlight and oxygen.

The new research, published in the Chemical Engineering Journal and led by The Department of Chemical and Biological Engineering’s Dr. Seetharaman Vaidyanathan, found that different strains of algae from a similar habitat can absorb varying amounts of phosphates and nitrates - key nutrients in fertilisers that also encourage algae to grow - potentially from wastewater streams before they get to lakes.

These nutrients could be removed and reused as biofertiliser, preventing the algae from growing in water bodies.

The difference in how much different strains of algae from a similar habitat can absorb is largely linked to factors such as the supply of carbon dioxide and nitrates and phosphates themselves, though this also varies between the different strains of algae.

The algae also has the benefit of drawing carbon dioxide from the atmosphere and capturing it, which is increasingly important in light of the UK’s goal of having net zero carbon emissions by 2050.

It’s hoped in the future that the data on how and why the algae absorb different amounts can be used to establish sustainable biomanufacturing routes that include the use of carbon capture via algae.

Indeed, the researchers are now looking to commercialise their findings, and are currently in talks with SMEs.

Dr. Vaidyanathan said: "The article provides evidence of how carbon, nitrogen and phosphorus supply regimes can differentially influence uptake of these elements even in microalgae from a similar habitat, suggesting considerable scope in the development of processes for abstracting these elements effectively from waste streams using microalgae to prevent algal blooms and address development of sustainable alternatives to fertilisers for use in agriculture."

The research, titled Nitrate and phosphate uptake dynamics in two halotolerant strains of Chlorella vulgaris is differentially influenced by carbon, nitrogen and phosphorus supply, was conducted in collaboration with researchers from the National Facility for Marine Cyanobacteria (NFMC)/National Repository for Microalgae and Cyanobacteria, Bharathidasan University, India, as a part of the SuBB project, which was supported by the Department of Biotechnology, Govt. of India and the UKRI Biotechnology and Biological Sciences Research Council.

The project also received financial support from the European Union’s 2020 New Horizons initiative and the UKRI EPSRC.

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