Decomposition of food waste from protein and carbohydrate sources by black soldier fly larvae, Hermetia illucens L.

Abstract

Aim: To determine the variability of black soldier fly larvae treatment in comparison to different sources of substrates with an emphasis on protein and carbohydrate with regards to black soldier fly larvae growth and the physico-chemical characteristics of the final compost. Methodology: The study comprised of an experimental setup, sample preparation of synthetic food waste (protein and carbohydrate source), physico-chemical and nutrients laboratory test and analysis of data. Results: The results showed that larvae that compost protein food sources are likely to be bigger than larvae that compost carbohydrate food sources. From the laboratory results, the amount of potassium, phosphorus, magnesium and C/N ratio content of protein source compost were 266.1 µg g-1, 204.3 µg g-1, 28.6 µg g-1 and 0.51 µg g-1 respectively. Whereas, the physico-chemical results for the carbohydrate source compost were 55.1 µg g-1, 20.5 µg g-1, 2.3 µg g-1 and 3.33 µg g-1 respectively. Interpretation: Black soldier fly larvae prefer to accumulate protein food residues rather than carbohydrate food residues, thus emphasizing that protein content is vital for their growth. The increase in potassium, phosphorus and magnesium for black soldier fly larvae yield compost can potentially produce organic solid fertilizer for farming and agricultural industries. The unfavourable nutrients from food waste is considered to be a significant factor that can affect the development, production and efficiency of life stage of composting black soldier fly larvae.