Insect biorefinery: Utilization of chitin, fats and proteins

Insect proteins are a sustainable and increasingly valuable food source for humans and animals. Some representatives of the insect kingdom are already being bred commercially under controlled conditions in order to obtain different product streams. Especially the commercially produced insect proteins have great potential as an alternative to soya protein and are already used as fish feed, for example.

Utilization of residues from insect breeding with insect biorefinery approach

Fraunhofer IGB is pursuing the concept of an insect biorefinery in which all material flows after insect breeding are used to create value. Thus, a sustainable insect biorefinery concept is realized by a holistic use of insect‑based products, such as protein, fats and chitin.

The aim is to produce new chemicals from insect fat in order to substitute fossil or tropical raw materials. We intend to use the biodegradable biopolymers protein and chitosan in technical applications and thus contribute further to the environment.

Organic waste, spoiled food and industrial kitchen waste have not yet been utilized sufficiently and are mainly recycled in composting plants.

Flies like to lay their eggs in the organic waste garbage can or on spoiled food, quickly resulting in the hatching of up to 1000 larvae per fly egg deposition. The larvae eat their way through the diverse organic waste until they are fully fattened after seven days, each larva reaching a length of 1-1.5 cm. The larva, but also the fly, is full of protein and fat. The skins of the larva and the body of the adult fly consist largely of the biopolymer chitin.

Insect biorefinery pilot plant at Fraunhofer IGB

We are utilizing this in our innovative approach and have set up our first insect biorefinery at Fraunhofer IGB within the InBiRa project, in which waste and residual streams are converted into new high-quality products.The project was funded by the Baden-Württemberg Ministry of the Environment, Climate Protection and the Energy Sector and the European Union as part of the ERDF (European Research and Development Fund) programme "Bioeconomy – Biorefineries for the recovery of raw materials from waste and wastewater".

In our insect biorefinery, we use Hermetia illucens, the black soldier fly, a fly and larva whose resistance to spoiled biogenic substances is particularly high.

Using (bio)chemical reactions, we can obtain dicarboxylic acids for polyesters, biosurfactants as soaps, lubricants and even biodiesel from the fat.

The two biopolymers protein and chitin/chitosan serve to produce biodegradable substances such as films for packaging, adhesives, coatings or thickening agents for paints or cosmetics.

Insect fat contains medium-chain fatty acids. It is chemically identical to tropical fats such as coconut oil or palm kernel oil and is the only domestic source of this type of fat.

Using (bio)chemical reactions, we can obtain dicarboxylic acids from insect fat as a starting material for polyesters, biosurfactants as soaps, lubricants and even biodiesel.

In the ChitoTex project, we were pioneers with regard to the chitin purification from insect skins. We have succeeded in producing high‑purity chitosan, using it as a sizing agent to protect yarns during weaving in the textile industry.

Due to its chemical structure including binding sites for additional functionalities, the renewable biopolymer is also suitable for sustainable finishing and fluorine-free hydrophobic processing of cotton, polyester and blended fabrics. We have investigated and successfully demonstrated this in the HydroFichi and ExpandChi projects.

We have investigated a further application of chitosan in the LaChiPur project: The modification with laccase to a biobased flocculant for the treatment of complex agro-industrial wastewater.

Fraunhofer IGB also intends to use insect protein in the future, for example in the production of packaging films, in order to provide a biodegradable alternative to synthetic plastics.

The protein content of insects is also suitable for the production of biobased adhesives, binders and coatings.