Kretsloppsteknik

My name is Tobias Eisert and I am a Master student in Agroecology in my final year. I started with a Bachelor’s degree in Organic Agricultural Sciences and now I am enrolled in EUR-Organic, a double degree Master between the University of Life Science (BOKU) in Vienna, Austria and the High Agronomic School (ISARA) in Lyon, France.

During my ERASMUS stay in Uppsala within my Bachelor’s I had the opportunity to discover the world of Black Soldier Fly (BSF) composting as an intern in the BSF group at SLU. Last year looking for a Master thesis brought me back to Uppsala and the research related to BSF composting.

During my stay here from February to May – the time of the experiments – I want to investigate potential improvements through a fungal pre-treatment for very wet waste streams – specifically vegetables.  To use this waste later for BSF composting as a substrates. I am glad that I got this opportunity working together with Dr. Cecilia Lalander and Viktoria Wiklicky during this time and also afterwards during the writing process of the Master thesis.

I am a master’s student at the University of Aveiro (Portugal), where I am currently studying the behaviour of nutrient leaching when different fertilizers – chemical and waste-derived – are applied in agricultural soils. One example of a waste-dervied fertilizer is the frass from black soldier fly (BSF) bioconversion. I am analysing distinct types of frass derived from different organic waste sources, including cereals and olive pomace, a toxic waste derived from olive oil production, which is a highly abundant waste in all the Mediterranean region. My research also includes ecotoxicological assessments of the leachates using model freshwater organisms, such as microalgae, duckweed and small crustaceans.

During my journey at SLU, for which I have the support of an ERASMUS scholarship, I will learn more about the steps preceding my thesis work, particularly the frass production process. I will work closely with Dr. Cecilia Lalander and Dr. Ivã Guidini and learn about the waste bioconversion process using BSF larvae. The research project we will carry out will investigate the pre-treatment of food waste using a species of fungus, followed by the bioconversion with the BSF larvae, in which we will access the chemical and biological quality of the resulting frass fertilizer.

Här pratar jag och Viktoria med Thomas Bjelkeman-Pettersson och Linnea Jäder i podden Matkretslopp om vår syn på insekters roll i våra livsmedelssystem.

 

In this review, published in Animal, Karol B. Barragán-Fonseca, Daipiero Gómez, Daniel Dzepe, Shaphan Y. Chia and I (Cecilia Lalander) investigate the current state of black soldier fly larvae (BSFL) farming in the global south. We surveyed as many producers we managed, and were able to collect data from 33 of the 100 producers we contacted: 14 in Africa, 4 in Latin America, and 15 in Asia. The review highlights the potential of Black Soldier Fly (BSF) farming has in the Global South as a sustainable solution for food production and organic waste management. By converting waste into valuable products such as animal feed and organic fertilizer, BSF farming aligns with the principles of a circular economy and supports sustainable development goals. The study emphasizes the region’s strengths, including favorable climatic conditions that reduce resource inputs and a long tradition of entomophagy, which facilitates cultural acceptance of insect farming. Smallholder farmers play a vital role in this emerging sector, and BSF farming offers them economic opportunities, such as reducing feed costs for livestock and aquaculture.

Despite its promise, the sector faces significant challenges. Producers encounter regulatory gaps, making it difficult to ensure compliance and market their products. Securing a stable supply of high-quality waste substrates is another major hurdle, while scaling up operations is constrained by technological and financial barriers. These challenges are further exacerbated by competition from conventional feed sources such as fishmeal and soybean meal, which are frequently more cost-effective.

Regional variations also influence the development of BSF farming. For instance, African producers use diverse organic waste substrates, while Asian producers tend to avoid manure due to cultural resistance. Latin America, by contrast, has fewer established facilities and producers, likely due to lower familiarity with insect farming and less institutional support.

The review underscores the growing market demand for BSF products, especially for animal feed and pet food. However, to fully realize the potential of BSF farming, there is a need for global collaboration among policymakers, researchers, and the private sector. Efforts to establish consistent regulations, improve waste substrate logistics, and develop scalable technologies will be critical for overcoming these barriers. If you are interested, read the full review here.

 

 

Over the last year, the BSF group has conducted exciting experiments as part of the Happy Salmon project. We received big batches of two species of macroalgae (Ulva and Saccharina) for the Nordic SeaFarm in Dingle, to be used as feed substrate for rearing BSF larvae. The algae was mixed with brewery spent grains, provided by Train Station Brewery in Knivsta and vegetable waste, ensuring a nutritiously balanced diet for the larvae. Interestingly, the larvae grew quite well in this blend substrate and achieved a high body protein (40%), while the fat content was considerably lower than our larvae usually are (< 15%), making this larval biomass a good feed ingredient.

The frass fertilizer obtained in these experiments also had interesting properties, having > 80% of organic matter and a NPK ratio of 3/1/3. However, the most exciting results regarding this frass fertiliser was the composition of beneficial microorganisms, stimulated by the presence of the algae in the larval diet.  Moreover, the frass container plant hormones,   including auxins, gibberellins and cytokinins, which are important regulators of plant growth and metabolism. These novel results are being investigated and assessed now to see how different plant species can benefit from frass when it is applied in the soil.

As a next step, the larvae produced with the macroalgae and brewery spent grains are being pressed and defatted, and then used as a nutritious feed ingredient for the production of fish feed. Skretting, a global leader in sustainable aquaculture nutrition, in Norway will use this feed in salmon growth trials. We believe that this BSF larvae-derived ingredient can be considered a more sustainable feed ingredient for aquaculture. Fingers crossed for interesting results to come!

The seminar is given in English and can be seen here.