Standardisation of fermented pellet feed of Tenebrio molitor larvae for use as a biodiesel raw material

To use mealworm (Tenebrio molitor larva) as a raw material for biodiesel production, after selecting three raw materials (wheat bran, mealworm frass, food waste) among 10 raw materials, WB50-FW50 (wheat bran:food waste = 50:50), which had the highest weight gain rate (WGR) and body fat content increase efficacy, was determined to be the optimal raw material combination. As a result of fermenting WB50-FW50 using microorganisms (Limosilactobacillus fermentum, Lactobacillus acidophilus, and Pediococcus acidilactici) with excellent enzymatic activities to increase the absorption rate in the body, WGR was increased by 40% compared to non-fermented WB50-FW50. To increase the value of the product and the convenience of distribution and use, we attempted to manufacture a pellet-type feed with a diameter of 6 mm and length of 10 mm. Based on the selection of inexpensive raw materials without adversely affecting viability and WGR, 0.05% sorbic acid was added as a preservative, and 20% agar was added as an excipient. The drying time after pellet moulding was determined to be 50 min, considering the high WGR, and the final pellet-type fermented mixed feed with sorbic acid and agar (PFMF) preparation was completed. Finally, compared to powdered wheat bran, a conventional mealworm feed, PFMF fed to mealworms increased WGR by 25.6% and body fat content by 18.8%. In conclusion, we suggest that the PFMF is a valuable feed with high economic feasibility, eco-friendliness, and convenience for breeding of mealworms for biodiesel production.