Producing insect protein from food waste digestate via black soldier fly larvae cultivation: A promising choice for digestate disposal

The treatment of food waste digestate with high salinity is a big challenge. This paper evaluated the possibility of using black soldier fly larvae for food waste digestate disposal and insect protein production. Results showed that both digestates from hydrogen and methane fermentations were rich in protein and lipid contents, which benefited the BSFL cultivation. The BSFL reared on digestates from hydrogen and methane fermentations of food waste performed better in pre-pupal weight (19.12% and 41.13% higher, respectively), body length (3.62% and 18.21% higher, respectively) and crude protein contents (7.85% and 39.05% higher, respectively) than that reared on raw food waste. In addition, the maximum body weight growth rate (Rm) of BSFL cultivated on both digestates were 28.28% and 47.10% higher than that of BSFL cultivated on raw food waste, respectively. During BSFL cultivation, organic matter reduction between 40.97% and 46.07% were achieved. Digestates from hydrogen and methane fermentations represent favorable feeding substrates for BSFL cultivation. Using BSFL to treat AD digestate not only provides a digestate disposal approach, but also produces insect biomass and organic fertilizer as value-added byproducts, which shows tremendous potential in digestate disposal.

Automated summary

This paper evaluated the potential use of black soldier fly larvae (BSFL) for the treatment and protein production of food waste digestate. The study found that the digestate from hydrogen and methane fermentations was rich in protein and lipid contents, which promoted the growth and protein production of BSFL. BSFL reared on the digestate performed better in terms of weight, length, and protein content compared to those reared on raw food waste. In addition, the digestate showed a significant reduction in organic matter during the cultivation of BSFL. The use of BSFL for digestate treatment not only provides a disposal method but also produces valuable byproducts, such as insect biomass and organic fertilizer.