Upcycling seafood waste

After finishing a large plate of steamed mussels, have you ever wondered what happens to the shells? While dining on planked salmon, do you think about the fish parts that don't make it to your plate? Of course not. It's just waste. Or is it really?

National Research Council of Canada (NRC) researchers at the Aquatic and Crop Resource Development Research Centre are upcycling seafood waste. As part of the NRC's Ocean program, our researchers are working with the Memorial University of Newfoundland to investigate how to cost-effectively repurpose seafood waste into products with commercial value.

It turns out that seafood wastes are full of amino acids chains, called peptides, with antioxidant and anti-inflammatory properties that make them a valuable natural resource. Peptides are commonly used in natural health products and to add nutrition to animal feed.

So, with a goal of finding new, high-value commercial products from the sea, 1 NRC research team has been studying discarded fish parts.

"By extracting the peptides, which are a valuable and commercially relevant product, directly from seafood waste, we are hoping to create new marine-based revenue streams for the Canadian fishery and aquaculture industries," says Dr. Zied Khiari, a research officer at the Aquatic and Crop Resource Development Research Centre. "It's essentially creating something valuable out of waste products."

Going green with a new process

These valuable peptides in fish and shellfish are released when proteins are broken down using specific enzymes called proteases. Traditionally, researchers purchased protease enzymes from commercial vendors. But that is expensive and they are not always easy to come by. So Khiari and his team are looking for easier and less expensive ways to extract the valuable peptides.

Ironically, the protease enzymes are found naturally in fish and shellfish. In fact, it is the reason seafood does not stay fresh very long. "Fish and shellfish go bad fairly quickly after a few days, even in the fridge," says Khiari. "That's because the enzymes are still actively breaking down proteins, even at low temperatures."

Khiari's team has developed a technology that effectively uses the naturally present protease enzymes to extract peptides from fish and shellfish wastes. "By manipulating the natural enzymes found in seafood wastes, we can release the valuable peptides in a much more efficient and cost-effective manner. It's an almost perfect example of a green process."

The team at Memorial University agrees. "My team and I were exploring innovative methods to convert and extract value from waste in the fishery and forestry sectors," shares Dr. Kelly Hawboldt, professor at Memorial University's Department of Process and Chemical Engineering. "This collaboration has yielded excellent results. Before partnering with the NRC, we relied on commercial enzymes to transform our waste materials into value-added products. Through this project, we adopted a truly circular approach by using 'waste' enzymes from fishery offal to treat another 'waste'—mussel processing shells."

Khiari sees this project as only a starting point in his search for value-added products from the ocean. "By using this type of green process, what was once considered waste becomes a resource," he says. "We just need to learn how to efficiently recover those resources."

In support of Canada's Ocean cluster, the Ocean program helps bring together the NRC's national network of researchers and facilities with partners from industry, academia, and governments to solve some of the most pressing ocean challenges, as well as supporting the growth of Canada's sustainable blue economy. The NRC's Ocean program collaborative research and development is funded through the Collaborative Science, Technology and Innovation program, administered by the National Program Office.