Alternative Proteins

Alternative sources of protein to meat and animal products have become an important pillar of the food industry and open up choices for a more sustainable nutrition. Fraunhofer IGB conducts research into new processes and biotechnological agricultural production systems for proteins from rapeseed, microalgae, fungi, bacteria, and cell cultures in order to contribute to food security with resource-efficient solutions.

Get in touch with us if you want to tap into new protein sources!

Depending on the technological readiness level, we can optimize processes for you and scale them up for market entry, conduct feasibility studies and provide sample quantities for further investigation, or jointly advance the development of new processes in funded projects.

To investigate the nutritional and food technology-related properties of proteins and protein biomasses, we collaborate with partners at the University of Hohenheim in Stuttgart and at Fraunhofer IVV in Freising.

You can find the contact persons at our institute at the bottom of this page and on the respective linked topic and project pages.

Rapeseed also contains relevant amounts of protein. In addition to oil, which accounts for around 40 percent of the ingredients, around 20 percent of the ingredients in rapeseed are the sought-after proteins. Rapeseed proteins are similar in composition to milk proteins and are therefore well suited as a plant-based protein source – for both food and animal feed. However, rapeseed proteins have not yet been used in food products. Conventional hot pressing of rapeseeds alters the structure of the proteins – the proteins denature. The rapeseed meal produced in this process also contains fibers and bitter substances from the rapeseed hulls. This impairs their suitability as animal feed, so that soybean meal is usually added to feed mixtures. 

EthaNa process delivers rapeseed concentrate with > 50 percent protein content

The process at the EthaNa^® pilot plant at Fraunhofer CBP is different: here, rapeseeds are gently broken down and fractionated with ethanol. Due to the mild process conditions (a maximum temperature of 70°C and normal ambient pressure), the structure of the rapeseed proteins is hardly changed during processing, allowing them to be used in a variety of ways. The extraction process is also preceded by a separate shelling plant to separate the oil- and protein-rich seeds from the fibers and bitter-tasting shells. The protein-rich rapeseed kernel concentrate, which the oilseed biorefinery supplies in addition to the husk fraction and the oil, is characterized by a high protein content of over 50 percent and a low residual oil content of less than 5 percent.

Perfectly suited as food and feed

Due to its high protein content and composition, the rapeseed kernel concentrate from the EthaNa process is ideal for use in protein-rich food products, as demonstrated in the Like-A-Pro project. It formed stable emulsions in combination with other ingredients, and burger patties impressed with good consistency, pleasant bite, and good mouthfeel. Furthermore, analyses showed a balanced amino acid composition that is beneficial for the human organism.

Rapeseed kernel concentrate is also ideal for use as animal feed due to its high content of essential amino acids, as confirmed in the NAPF project. In addition, studies conducted by the University of Hohenheim showed that rapeseed kernel concentrate has better protein digestibility than rapeseed extraction meal. When the enzyme phytase was added, the protein digestibility of the rapeseed kernel concentrate feed was further increased. 

Microalgae produce polysaccharides, important omega-3 fatty acids, carotenoids, vitamins – and also proteins. This makes algae interesting for use as nutritionally balanced food or feed. They can be processed directly into food or in dried form.

Like plants, algae grow photosynthetically with light and bind the greenhouse gas CO_₂ 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 – independent of seasonal or climatic factors.

Modular photobioreactor platform for economical 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, are modularly scalable when coupled. Lighting is provided by energy-saving LEDs. Remote maintenance enables automated operation at any location on-site as drop-in technology.

Depending on the target product, nutrient-rich side streams can also be used for cultivation, thus closing resource cycles.

Microalgae as an alternative to fish

In the food sector, the omega-3 fatty acid content of algae makes them an ideal alternative to fish – a worthwhile option given the overfishing of the world's oceans. Possible applications and nutritional parameters for the microalgae Phaeodactylum tricornutum have already been investigated in a project conducted in collaboration with the Institute of Clinical Nutrition at the University of Hohenheim in Stuttgart.

Analyses have shown that dried microalgae contain not only a protein content of almost 50 percent in dry matter, but also significant amounts of the long-chain omega-3 fatty acid eicosapentaenoic acid, or EPA for short. According to an initial study by the University of Hohenheim, microalgae are suitable for meeting the daily requirement of omega-3 fatty acids. They also contain water-soluble fiber, which is important for intestinal health, as well as vitamin E and carotenoids. The composition of the ingredients can be controlled by adjusting the culture conditions in the Fraunhofer IGB's photobioreactor. If the algae are supplied with sufficient nutrients, they produce particularly high levels of EPA. If the algae grow under nutrient limitation, they form more fiber.

The use of algae as food also falls under the Novel Food Regulation. Some types of algae are already approved as food. The microalgae Phaeodactylum tricornutum is already used in animal feed, but is not yet approved for use as food.

Fungi contain a high-quality protein for human nutrition, also known as mycoprotein. Due to its consistency, texture, and taste, it is suitable for use in meat substitute products. Mycoprotein also contains fiber, unsaturated fatty acids, important nutrients, and vitamin B12.

Fungal mycelium is produced in bioreactors, as is single-cell yeast (see fermentation). 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. Mycoprotein is already being produced industrially on the basis of the mold Fusarium venenatum. Current research is focusing on the production of protein-rich fungal mycelia through submerged culture of basidiomycetes. These fungi, also known as stalked fungi, include shiitake and oyster mushrooms, for example.

Many years of experience in the submerged cultivation of basidiomycetes

One challenge in the submerged culture of basidiomycetes in bioreactors 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 with 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 hyphae formation on food industry by-products

In the Fraunhofer FutureProteins flagship project, Fraunhofer IGB has succeeded in developing the 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. Fermentation optimization for the edible mushroom Flammulina velutipes included pre-culture management, stirrer geometry and speed regime, gas supply rate, and investigation of the optimal C/N ratio in the substrate. 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 F. velutipes mycelium and high solubility.

In addition, the team planned and designed the 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 on the basis of the mass balance and fermentation capacities to be adjusted. Furthermore, it can be used to estimate the investment costs and energy requirements of larger plants.

Fermentation is a key biotechnological process in alternative protein production. While classic fermentation processes such as lactic acid and alcoholic fermentation have been used for thousands of years to preserve and produce food, precision fermentation uses specifically selected or genetically modified microorganisms – e.g. yeasts or bacteria – to convert substrates into the desired products, such as milk, egg, or meat proteins, in a controlled fermentation process.

Fermentative production of single cell protein (SCP)

Fermentatively produced protein-rich biomass from microorganisms such as bacteria and yeasts (or also from microalgae or fungi) is referred to as single cell protein. The protein content varies between 30 and 80 percent depending on the organism. It is considered a sustainable alternative to soy or fish meal for animal feed, but can also be used in the food industry to produce dietary supplements, baking ingredients, whey substitutes, or probiotics. Depending on the intended use, either the whole cells or a protein extract are dried for further processing.

As an alternative to classic protein isolation, the fermentatively obtained biomass can also be processed directly as a whole. Extrusion can be used to convert the microorganism biomass into a fibrous texture that is ideal as a basis for meat or fish analogues. Microorganisms that are particularly rich in oil offer nutritional benefits, as they are rich in unsaturated fatty acids such as omega-3 and omega-6, as well as B vitamins. These ingredients contribute to a balanced diet and make the products attractive not only in terms of taste but also in terms of health.

The industrial biotechnology working group at Fraunhofer CBP, the Leuna branch of Fraunhofer IGB, develops and scales up fermentations on behalf of customers for the production of precursors and products for food, dietary supplements, and animal feed.

Strain development at Fraunhofer IGB Straubing branch

Fraunhofer IGB offers state-of-the-art methods for strain and fermentation process development through to upscaling and piloting as an integrated all-in-one solution and also supports companies in transferring their processes to industrial scale.

The first step, the design of suitable production strains for milk or meat protein, takes place at Fraunhofer IGB in Straubing. Using model-based methods and metabolic engineering, efficient and tailor-made high-performance production strains are created for your products. Alternative approaches are also available for applications where the use of genetically modified organisms (GMOs) is not desired. For example, suitable wild types can be selected that already have the desired characteristics by nature and can be used for the production of certain proteins. In addition, there are non-genetic methods for optimizing microorganisms, such as adaptive evolutionary selection, targeted adaptation of culture conditions, or classical mutagenesis. These methods make it possible to specifically improve the performance and yield of organisms without resorting to genetic engineering. In this way, protein production can be successfully designed while taking regulatory or social requirements into account.

Pilot plants for scale-up as a bridge to the market

Fraunhofer CBP provides start-ups, SMEs, and large companies with its equipment and expertise for scaling up and optimizing fermentation processes as well as the associated downstream processes. With the help of automated, sterile bioreactors up to 10 m³, sample quantities can be produced on a kilogram to ton scale and process parameters can be obtained for transfer to industrial scale.

In the US, the first laboratory-produced dairy products are already on the market. Milk proteins produced using modern biotechnological processes such as precision fermentation fall under the Novel Food Regulation in the EU. Since these proteins are not produced by cows but by genetically modified microorganisms, they are considered novel foods.

Dairy products produced by precision fermentation are considered resource-efficient and climate-friendly, requiring no agricultural land and only a small amount of water. Initial estimates suggest that precision fermentation can save up to 90 percent of water compared to conventional milk production. In addition, biotechnological production delivers consistent quality throughout the year, regardless of seasonal fluctuations.

Meat grown in cell cultures in the laboratory – in-vitro meat, lab meat, cultivated meat – is considered a genuine alternative to meat from traditional agriculture in terms of taste and texture. The idea is to produce high-quality meat without animal husbandry and the associated negative effects on the environment. In particular, the environmental balance can be more favorable in terms of land use, water consumption, and greenhouse gas emissions.

The meat substitute is produced biotechnologically using cell cultures. To do this, stem cells are extracted from muscle tissue from chickens, pigs, or cattle, for example, and cultivated in a nutrient solution under controlled conditions in the laboratory. During growth, the cells go through various stages and finally form muscle fibers. As with other cell culture-based processes, bioreactors are used to produce larger quantities of cells. Several products made from cultured meat have now been approved in Singapore, the US, and Australia. Cultured meat is not yet available in Germany. Several applications for approval as a novel food have already been submitted in Europe.

Cost-effective culture media without animal components

The cells need nutrients as well as specific growth and differentiation factors or transport proteins in order to grow and differentiate into muscle cells. Fetal bovine serum, which is obtained from the blood of unborn calves, provides all these components. Alternative initial approaches are based on algae, fungi, protein-containing plants, and synthetically produced growth factors. The team at Fraunhofer IGB is also investigating cost-effective, defined, and completely animal-free nutrient solutions based on, among other things, residues and by-products from the food and dairy industries.

Cell lines from cattle, pigs, chickens, and fish

In addition, the team develops non-genetically modified cell lines, primarily fat and muscle precursor cells from cattle, pigs, chickens, and fish. The team refines methods for isolating and propagating animal cells and specifically directing their maturation toward desired characteristics such as nutrient profile, taste, and texture. One focus here is on scalable processes in the bioreactor. This is accompanied by process analytical methods to track growth and nutrient consumption in real time.

Shaping the products

In order to achieve the right texture and stability in meat products, degradable or edible and scalable carrier structures are required for shaping. The Kluger team is developing support structures and edible bio-inks for this purpose in order to shape the muscle cells using various 3D bioprinting processes. Depending on the target product, either pure cell constructs are created or hybrid products combined with plant substances.

All processes are designed for food suitability from the outset. Prototypes are therefore tested using food analysis methods, for example for nutrient profile, texture, shelf life, frying behavior, and appearance.

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.

The Fraunhofer FutureProteins flagship project therefore also focused on using waste materials as far as possible for the production of further protein raw materials. By linking the various production systems developed in the project, side streams could be efficiently utilized. For example, plant residues served as a substrate for the cultivation of insects, fungi, and algae, nitrogen-rich side streams from insect production served as plant fertilizers, and waste heat was used for air conditioning.

Digital tools and methodology for monitoring material and energy flows

The development of such a closed agricultural system, which takes into account concepts of the circular economy – reducing waste and making optimal use of resources – required careful planning and analysis of all material and energy flows based on the technical modules set up on a pilot scale. For such a comprehensive system, concepts were developed at Fraunhofer IGB for the material use of generated solid, liquid, and gaseous residues, as well as for the energetic use of waste heat and gaseous energy sources from an affiliated biogas plant.

To this end, the institute established a methodology for recording and analyzing material and energy flows. Primary data on material and energy requirements were integrated into a model for material and energy flows. Simulations 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 take 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 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.

How sustainable alternative protein sources really are, depends largely on the production method, which is still in development for many new proteins. Plant-based proteins generally require fewer resources than animal products, while microalgae and microorganisms are appealing due to their low space requirements.

However, these systems, like cell cultures, require electrical energy to operate the plant technology. Initial simulations and model calculations indicate that alternative protein sources can make an important contribution to sustainability if renewable energies and by-products and waste streams are used for production.