Production of Protein Hydrolysate and Biodiesel from Black Soldier Fly larva Cultivated using Rotten Avocado and Tofu Residue

The larva of Hermetia illucens L. (black soldier fly larva) can convert various types of organic to produce protein and lipid rich biomass which can be further valorized to produce valuable bioproducts. This study was carried out to investigate the potential application of tofu residue and rotten avocado as substrates for the cultivation of black soldier fly larvae as an alternative feedstock to produce protein hydrolysate and biodiesel. The larvae were cultivated for 24 days in a screen house (temperature range of 19–30 ° C, relative humidity of 35–95%, and light intensity of 0.03–20 W/m 2 ). The larvae were fed with tofu residue and rotten avocado once every three days. After 24 days of cultivation, the larvae were harvested with a biomass weight of 233-267 mg/larvae and larval length of 2.2-2.3 cm. The harvested biomass had total protein and lipid content in the range of 21.2-47.2% and 20.8-28.9%, respectively. Lipid isolated from the harvested biomass was reacted with methanol and lipase to produce biodiesel which mainly composed of fatty acid methyl laureate (19.2-28.7%), fatty acid methyl oleate (22.1-23.7%), and fatty acid methyl linoleate (15.4-:21.1%). The ester content, acid value and iodine number of the produced biodiesel were also determined. The defatted biomass was hydrolyzed with 5% bromelain enzyme to produce protein hydrolysate with the degree of hydrolysis and productivity of the protein hydrolysate lies in the range of 46.7-52.6% and 0.02-0.04 g/ml/batch. Amino acid in the protein hydrolysate was determined and mainly composed of glutamic acid (16.5-18.2%), alanine (16.7-18.1%), lysine (9.1- 9.4%) and valine (7.9-8.5%).

The authors declare no conflict of interest.

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The datasets used in this study are openly available at [repository link] and the source code is available on GitHub at [GitHub link].

This work did not receive any external funding.