Recycling food processing waste in NZ

A research project led by University of Canterbury Environmental Science Professor Brett Robinson aims to find ways to turn waste products from New Zealand’s food production industry — such as milk processing waste and grape marc (skins and stalks) — into high-value soil conditioners and animal feed.

According to Robinson, about 2.2 million tonnes of food processing waste products are dumped each year in New Zealand — costing about NZ$270 million a year and increasing greenhouse gas emissions.

“What we are aiming to do is create a more sustainable, circular agricultural economy, where biowaste can be transformed into useful new products to help feed animals or improve our soils.

“There’s huge potential to create a win-win situation where we dramatically reduce greenhouse gas emissions while also potentially boosting our economy by more than $1.6 billion annually.”

The research team is working with 21 food processing companies that are part of Venture Timaru who are keen to explore recycling options for their waste.

“It’s largely driven by industry,” Robinson said. “We’re developing the science in response to industry demands.

The project aims to use microorganisms, extracted from plants as agents to transform food processing waste into valuable products.

Robinson is leading a team of scientists from the University of Canterbury along with experts from Lincoln University (led by Dr Racheal Bryant), Plant and Food Research (led by Dr Brendon Malcolm) and Manaaki Whenua Landcare Research (led by Dr David Whitehead and Dr Manpreet Dhami).

Manaaki Whenua Landcare Research has a unique, curated collection of over 20,000 strains of bacteria and fungi from plants around the world; the New Zealand International Collection of Microorganisms from Plants (ICMP).

Machine learning methods would be used to select microbes that can transform particular biowastes — such as grape marc and milk processing waste — efficiently into new products such as soil conditioners and animal feed.

“We want to create economic and environmental value from biowastes by ensuring the nutrients they contain are harnessed to improve our soils and feed our animals rather than degrading our waterways and contaminating soil,” Robinson said.

New Zealand’s milk processing industry produces nearly 800,000 tonnes of solid biowaste and 190 billion litres of liquid effluent annually. Robinson said bioreactors at milk processing plants could transform this waste into a valuable soil conditioner instead of it being disposed of on nearby land.

Robinson estimates the potential economic benefit of the research is more than $1.6 billion a year from reduced disposal costs, new product sales and reduced reliance on imported products, such as phosphate fertilisers and palm kernel expeller (PKE), which is used as animal feed and costs about $300 million a year. It could also reduce greenhouse gas emission penalties by an estimated $178 million a year.

Image credit: ©stock.adobe.com/au/Christian