SymBioOekonomie: Insects and their symbiotic microbes for the circular bioeconomy

Increasing awareness of the economic and, in particular, ecological consequences of conventional factory farming, coupled with a steadily growing world population, calls for the development of alternative protein sources on a large scale. The provision of insects as food and feed through insect farming offers great potential and contributes to food security.

One of the biggest problems in livestock farming and aquaculture is the use of feedstuffs such as soya and fishmeal, which contribute to the deforestation of rainforests and overfishing of the oceans. The feeding of fishmeal, which is often contaminated with fish pathogens, also necessitates the use of antibiotics, which has a negative impact on water quality and food safety. For these reasons, feed insects are currently being developed as ecologically acceptable alternatives. However, the economic competitiveness of insects is limited by the availability of cheap insect feed and requires better utilisation of residues and side streams from industry and agriculture.

Food production is particularly dependent on the availability of mineral fertilisers. Due to high energy prices and limiting resources such as phosphate, the use of artificial fertilisers is becoming increasingly expensive. It also contributes to the emission of nitrogen oxides and the leaching of nitrate into aquatic ecosystems. Therefore, alternatives in the form of organic fertilisers are increasingly needed for agriculture.

The overarching goal of the SymBioÖkonomie project is the research and development of symbiotic microorganisms from insects as a link for the realisation of a climate-friendly, circular bioeconomy under low- or zero-waste conditions.

In order to enable resource-saving insect breeding, our project is evaluating residual materials and low-cost side streams from industry and agriculture as food for the larvae of the black soldier fly (Hermetia illucens). The larvae are to be bred efficiently using microorganisms that break down plant components of the side streams that are difficult to digest.

The project aims to use the larvae as feed for aquaculture. The larvae are to be bred in such a way that the use of antibiotics in aquaculture can be reduced by feeding them. When breeding insects, the formation of greenhouse gases is to be evaluated and, if necessary, minimised by adapting the breeding conditions. In insect farming, the so-called frass (consisting of faeces, feed residues and insect exuviae) is produced as a residual material/by-product. This is characterised microbiologically and chemically in our project and tested as a fertiliser on crops in order to develop alternatives to mineral fertilisers.