Moving towards circularity: microbial and chemical characterization of waste-based fertilizers from black soldier fly larvae treatment of organic materials

The aim of this project is to investigate the real agronomic potential of the treatment residue (frass) from black soldier fly larvae (BSFL) treatment, a resource than can assist in closing the loop of plant nutrients from urban centers to agricultural land, which is a necessity for the transition into a circular economy.

Frass is considered a sustainable biofertilizer that contains several plant nutrients; however, not much research has been done on it.

Thus, in this project, abundant waste streams in Sweden will be used as feed substrate for BSFL and the produced frass, which is typically an immature compost, will be investigated in relation to its stabilization over time in thermophilic composting and vermicomposting.

Subsequently, in the attempt of assessing the frass’ microbial composition of bacteria and fungi and its mode of action in the soil-root-plant system, frass’ microbial profile will be assessed through 16S rRNA genomic sequencing, followed by generalized proteomics and peptidomics evaluations, screening for small proteins, peptides and amino acids of agricultural interest.

In addition, this waste-derived fertilizer will be evaluated for its composition of bioactive compounds (e.g. phytohormones, humic and fulvic acids), which drive the lesser-known organic-linked plant growth processes and can be harnessed to improve plants metabolism, crops productivity and plants resistance to conditions of abiotic stress.