Waste-powered feed could help tackle overfishing

AIBN researchers have developed a production process that converts organic waste into biogas to grow a high-protein alternative to fish feed.

The fermentation technology, developed at the UQ Biosustainability Hub, transforms organic waste into animal feed and could help ease an overreliance on fishmeal made from wild-caught fish, used in aquaculture.

A patent has been secured by the researchers for the biogas conversion production process.

Rethinking fish feed

Dr Lars Puiman, said aquaculture has become one of the world’s fastest growing food production sectors in recent decades.

“Fish farming industries have traditionally relied on fishmeal – a practice that harvests large quantities of small wild-caught fish including anchovy,” Dr Puiman said.

“This can lead to overfishing, depleting fish populations and draining the ocean’s resources, as well as creating long emission-intensive supply chains.”

“With farmed seafood estimated to make up about 62 per cent of all seafood produced globally by 2030, finding ways to make fish farming more sustainable is important to supporting efforts to reduce pressure on marine ecosystems impacted by overfishing.

“Australia’s aquaculture industry is paving the way in becoming more sustainable.

“Our technology aims to support this, assisting ongoing efforts from the aquaculture industry to move away from fishmeal.”

Producing a sustainable protein

The fermentation technology, , uses carbon dioxide and methane naturally produced when organic waste is broken down by microorganisms in an oxygen-free environment.

Produced through a process called ‘anaerobic digestion,’ these gases are used in the process to grow protein-rich cells.

“Once harvested, the cells are processed into a high-protein ingredient called ‘single-cell protein,’ which is a nutritious supplement with similar properties to fishmeal, and has potential to act as a sustainable substitute,” Dr Puiman said.

Giving carbon from waste a second life

Dr James Heffernan said the process could expand to produce sustainable alternatives for other animal feeds and soil fertilisers.

“The process reuses carbon from organic waste to produce fish feed while helping to minimise the need for additional emissions,” Dr Hefferman said.

“Australia’s agriculture industry is also a major part of the economy, and we can use the technology to easily convert gases generated by agricultural waste into an alternative fish feed.”

Dr Puiman said replacing fishmeal entirely remains a long-term goal, but studies have shown that microbial single-cell proteins can replace up to 75 per cent of fishmeal in barramundi diets – a key sector of Australia’s aquaculture industry.

The technology is currently under development, with researchers’ next steps to trial the product at a pilot scale ahead of testing on aquaculture feeds.

“Ultimately we are working towards developing a cost-effective solution that has the potential to deliver environmental benefits,” Dr Heffernan said.

Collaboration and acknowledgements:

This media release has been prepared and issued by the University of Queensland.

The University of Queensland wishes to acknowledge Woodside Energy as a funding partner that has supported the development of the new production process.

The statements, opinions and views expressed in this media release are those of the University of Queensland and its researchers based on the work they have undertaken, and do not necessarily reflect the views, opinions or position of Woodside Energy.