In recent years, the industrial use of certain insects such as the black soldier fly (BSF, Hermetia illucens) has become a burgeoning way of converting residual biomass into valuable resources for biomolecules, including proteins, lipids, and chitin suitable for the feed and food industry. A broad spectrum of organic residues ranging from agro-industrial by-products to animal manure qualifies for this process. In contrast to other means for valorizing organic matter, interposing this insect-based bioconversion step can directly close the loop back to the source of most organic waste – i.e. the production of food and feed. In addition to generating a valuable nutrient source for traditional livestock, the rearing residues rich in insect excrements and chitin can find application as efficient organic fertilizer. With the steadily expanding support from the EU commission and the contribution to the Green Deal’s goals, this technology shows promising potential to save organic resources and at the same time reduces the reliance on unsustainable, imported feeds.
In this project, we propose the integration of another valuable process step into the waste valorization process, namely the production of the highly active biopolymer chitosan. Without doubt, chitin and its derivative chitosan are attractive biopolymers that are already widely used in the industry. Chitosan in particular, is being intensively investigated and harbors enormous potential for future industrial applications for agriculture, wastewater treatment, sanitation, and pharmaceutics.
Our goal is to pave the way for sustainable chitosan production from insect-based resources in addition to high-quality protein, lipids, and fertilizers, by improving the technological expertise at the plant of the startup company LIVIN farms AgriFood GmbH.
First, the total amino acids and the N-acetylglucosamine content of the harvest-ready larvae will be determined and put in relation to their feeding conditions at the company LIVIN farms.
By hooking into the LIVIN farms biomass separation process specialized on the extraction of lipids and proteins, the resulting defatted and deproteinised larval biomass pulp will be processed using gentle conditions. Thereby, this previously untapped fraction of residual larval biomass will be targeted to recover high quality protein and chitin suitable for the food industry. The dried residual biomass is delivered to the FH Campus Wien, where we will evaluate the feasibility of using various enzymatical or chemically assisted extraction protocols to obtain chitin and chitosan fractions. We will use our profound knowledge gained from two FFG projects on chitosan extraction from fungal cell walls and apply these established procedures to prove whether and which enzymes can also be used for the BSF-derived matrices. In this regard, it will be crucial to expand our portfolio by screening for new highly specific biocatalysts with increased activity on the BSF matrix to produce chitosan with high quality and purity in an ecofriendly and economic way. This search for new target enzymes that specifically become active during the hydrolysis of the larval matrix, will be carried out as an RNA-Seq transcriptome approach by the scientific partners at the University of Innsbruck. The expression profile of target enzymes will be analyzed and promising candidates will be selected for optimized bioconversion processes.
Finally, the quality of the products will be determined using established bioassays in our laboratory based on the biocidal efficacy on various bacteria and fungi.
The proposed proof-of-concept study expands the product portfolio of the start-up LIVIN farms AgriFood GmbH and the core competence of the participating scientific partners with regard to the sustainable production of the highly potent product chitosan for diverse industrial applications.