News Circular economy, Fish, Forestry

The MonoCell project of the Natural Resources Institute Finland (Luke) has produced single-cell proteins from sawdust. Proteins can be used, for example, to produce fish feed. This means that the forest industry’s side streams would end up for human consumption.

New sources of sustainable protein are highly in demand. Sawdust can be one of them. Photo: Lucia Blasco.

Sawmills in Finland produce 3.3 million cubic metres of sawdust every year. The majority of sawdust is used in the production of pulp and energy, while a significant volume remains unused. Therefore, sawdust is nearly regarded as hazardous waste at many sawmills. Now, there might be a solution to deal with the waste – and create additional income for sawmills.

In the process developed in the MonoCell project, sugars found in sawdust are split so that a single-cell organism, in this case yeast, can use the sugar as nutrition. Conditions were adjusted so that the process mainly produces proteins instead of ethanol.

“I’m very happy that as a result of Luke’s multidisciplinary cooperation, we now have a tangible product and an entire process to produce sustainable domestic proteins,” says Risto Korpinen from Luke who heads the project.

Other members of the project team were Lucia Blasco, Rina Bragge, Minna Kahala, Vesa Joutsjoki, Kalle Kaipanen, Marja Kallioinen, Petri Kilpeläinen, Sari Lassila, Jarkko Mäkinen, Nora Pap, Anne Pihlanto and Jouni Vielma.

New business for forest industries

The production of single-cell proteins could be integrated, for example, with the operations of pulp mills. The lignin found in sawdust can’t be used in the production of proteins, but it could be used to produce the energy required by the process.

Korpinen says that wood-based proteins could be used as fish feed, which requires large amounts of high-quality proteins. This innovation would increase the protein self-sufficiency of feed and also reduce the field area required for the production of fish feed.

“In Finland, supplementary proteins imported from other countries, such as soy, are used in large quantities in Finnish fish feed. The fish industry is lacking a sustainable domestic option. In other countries, wild-caught fish is also used as fish feed, which has pushed global fish stocks to the verge of collapse.”

Next, the MonoCell project will identify the amino acid composition of proteins and, in a potential further project, feed will be produced from proteins for testing in fish farming. Furthermore, Luke is running other projects to study the use of new sustainable sources of proteins in fish feed.

Wood-based proteins are not intended to be used directly for human consumption, but Korpinen has already tasted the product.

“It actually tasted quite good, with a little salty flavour.”