Fraunhofer Flagship Project “FutureProteins”

The sustainable production of insect proteins as feed for livestock and food for humans represents a globally booming alternative to conventional protein sources such as meat and dairy products. Since January 2018 the EU’s Novel Food Regulation has allowed foods made from insects to be marketed in Europe. The first food insect farm in Germany has been in operation since 2019.

Insects as protein source: Need for pathogen detection

However, the production of insects on an industrial scale also promotes the spread of diseases, which can lead to the collapse of insect breeding, production losses and thus serious financial losses. In addition, the insect-based food must be free of human and animal pathogens. A specific and efficient detection system for pathogens in insect farms that is automated, digitized and capable of high-throughput, and that can deliver results promptly and on site, is still missing.

Currently, classic, culture-dependent methods or metagenomic approaches are applied to identify microorganisms in the gut and in the breeding tanks of insects. Both approaches are expensive, time-consuming and tedious, and thus not suitable for daily routine inspections in insect farms.

DNA-based detection of insect pathogens

As part of the FutureProteins lighthouse project, the IGB is developing an automated monitoring system for insect farming together with the Fraunhofer institutes IME and IVV: For this purpose, a molecular detection system covering the eleven most important insect-associated pathogens is being developed at the IGB.

Using insect sample material, DNA signatures of the pathogens are amplified and fluorescently labeled using an isothermal amplification technique. Specific binding to an immobilized probe results in a fluorescent signal that is identified optically and evaluated using a simple matrix. This technique allows for much easier handling than the commonly used PCR applications. In the future, the detection system developed for routine inspection at production sites will be integrated into a partially or fully automated inline system and can ultimately help to minimize the use of antibiotics and promote the resource-saving production of proteins.

Fungi contain a high-quality protein for human nutrition, also known as mycoprotein. The biotechnological production of fungal mycelium takes place in bioreactors in liquid culture media (submerged cultivation). In contrast to solid-state cultivation with fruiting bodies, mycelium can be produced more quickly and under controlled conditions in bioreactors, even on an industrial scale. The fungi grow on substrates containing starch, sugar, and minerals, for which industrial waste streams such as molasses, apple pomace, or spent grain can generally be used.

Fraunhofer IGB with long-standing experience in the submerged cultivation of basidiomycetes

One challenge in the submerged culture of basidiomycetes in a bioreactor is controlling fungal growth: the fungi should grow in the form of small mycelium balls and not form hyphae. These long, filamentous cells increase the viscosity in the reactor and cause the mycelium to grow “stuck” which makes mixing in the reactor and the supply of oxygen and nutrients more difficult.

The industrial biotechnology team at Fraunhofer IGB in Stuttgart has been working for many years on the production and optimization of glycolipid biosurfactants using strains of the Ustilaginaceae family, which also belongs to the Basidiomycota, and has thus been able to build up extensive expertise in submerged culture.

Optimized fermentation without hyphen formation on by-products from the food industry

In the Fraunhofer FutureProteins flagship project, Fraunhofer IGB has succeeded in developing submerged cultivation of basidiomycota on by-products from the food processing industry. Fermentation was first investigated on starch-rich potato pomace and potato peelings and then transferred to potato pulp, which is produced during the industrial extraction of starch from potatoes.

From over 100 fungi, initial candidates for cultivation on potato residues were first identified in the project (Fraunhofer IME) on the basis of screenings. After initial investigations, the edible mushroom Flammulina velutipes, the common velvet foot mushroom, was selected for submerged culture and further fermentation optimization at Fraunhofer IGB. These included pre-culture management, stirrer geometry, gas supply rate, and investigation of the optimal C/N ratio in the substrate. By introducing a new speed regime during mixing, the proportion of firmly attached mycelium was reduced, the amount of mycelium formed was doubled, and the space-time yield was increased. Fermentation was gradually scaled up to a scale of 300 L (with a working volume of 200 L).

Analyses by Fraunhofer IVV revealed a favorable amino acid profile of the mycelium of F. velutipes. The protein-rich mycelium is also characterized by high solubility, making it suitable for use in fillings for baked goods or pasta, for example.

Engineering design of the fermentation process

In addition, the team at IGB planned and designed the entire fermentation process of F. velutipes on potato pulp for upscaling – from media preparation to product extraction. The flexibly designed model allows material flows to be determined based on the mass balance and fermentation capacities to be adjusted. Furthermore, it can be used to estimate the investment costs and energy requirements for future plants at industrial partners.

Just like plants, algae that grow photosynthetically using light bind the greenhouse gas CO₂ during growth. However, their production does not require arable land and requires less water. The single-celled organisms can be cultivated in open ponds or basins, or under controlled conditions in closed, vertical systems – regardless of seasonal or climatic factors.

A modular stack photobioreactor system with LED lighting, automation, and CO₂ recycling developed in the project enables efficient microalgae production. Chlorella vulgaris and Phaeodactylum tricornutum provided biomass with up to 50% protein, suitable for applications in food, feed, and bio-based processes.

Modular new stack photobioreactor system

To achieve the objectives, a prototype of a compact modular photobioreactor was designed, planned, and constructed. A new lighting concept was integrated, the existing control concept was expanded, and the new prototype was put into operation:

• The degree of control and automation was increased through the integration of sensors.
• Exhaust air recycling was established and CO₂ utilization was significantly increased.
• By switching from single-sided to double-sided lighting in the compact modular photobioreactor, the conversion of light into biomass productivity increased while maintaining high light yield.
• Testing of new energy-efficient LEDs
• Provision of protein-rich algae biomass

Technology platform for economical algae cultivation

With its flat-panel airlift photobioreactors (FPA-PBR), Fraunhofer IGB provides companies with a technology for producing algae biomass with outstanding productivity, product quality, and cost efficiency. The individual reactor modules, each with a volume of 125 liters, can be scaled modularly by coupling them together. Lighting is provided by energy-saving LEDs. Remote maintenance enables automated operation at any location on-site as drop-in technology.

To ensure that alternative protein sources can contribute to a sustainable food supply for the future, production systems must also be evaluated, designed, and configured with regard to their resource and energy efficiency. If strategies for material cycle concepts are embedded in regulatory frameworks, for example through sustainability certificates and CO₂ pricing mechanisms, circular systems could become the new norm in protein-based agriculture and support the transformation of food production.

Digital tools and methodology for monitoring material and energy flows

To this end, the institute has established a methodology that records and analyzes material and energy flows. Primary data on material and energy requirements for the developed cultivation systems and processing technologies were integrated into a model for material and energy flows. Simulations then enabled the prediction of material and energy balances on an industrial production scale. Simulation models for preferred energy concepts were developed for the overall system and combined with models of specific plants. Based on the material flow and energy models, comprehensive operating concepts were developed that also took into account external material and energy sources as well as energy storage and conversion systems. By defining evaluation criteria such as the degree of self-sufficiency, it was possible to design the overall system in the best possible way in terms of circular economy and sustainability.

Systematic analysis as a basis for further process optimization

Careful balancing of material and energy flows also allows for the systematic investigation of production and conversion processes in other cases. This makes it possible to understand material and energy flows and to evaluate process efficiency and resource utilization. Optimization potential can be clearly identified and targeted measures to increase resource efficiency and sustainability can be derived.

Circular economy concepts as a contribution to the transformation of food production

If strategies for material recycling concepts are embedded in regulatory frameworks, for example through sustainability certificates and CO₂ pricing mechanisms, circular systems could become the new norm in protein-based agriculture and support the transformation of food production.