Life Cycle Assessment of Chemical vs Enzymatic-Assisted Extraction of Proteins from Black Soldier Fly Prepupae for the Preparation of Biomaterials for Potential Agricultural Use

The cradle-to-grave life cycle assessment (LCA) was applied to the preparation of biomaterials derived from proteins, extracted from black soldier fly (BSF) prepupae, after the larvae were reared on poultry manure-based organic waste. To obtain higher value-added biomolecules, extraction represents the fundamental step. Therefore, the environmental sustainability assessments of different extraction/fractionation procedures were compared. In this way, it is possible to consider also their environmental performances in addition to the purity, yield, and integrity of the extract. A chemical method characterized by a one-step protein extraction was compared to an enzymatic-assisted protocol, employing Bacillus licheniformis protease. Surprisingly, the enzymatic approach resulted for the 31.87% more environmentally impacting with respect to the chemical method, despite its lack of organic solvents and reduction of alkaline and acid solutions employed. Particularly, the long time necessary for the enzymatic hydrolysis significantly contributed to the environmental impact of this protocol. Therefore, improvements such as biomass pretreatment procedures or the use of different proteolytic enzymes (e.g., operating at lower temperatures and in shorter times) are needed. Moreover, to reduce the environmental load of the protein fraction, attention should also be given to increase extraction yields of lipids and chitin biomolecules obtainable from BSF prepupae, due to the biorefinery approach under which this study was considered.