Abstract: 【Aim】To establish a highly efficient “bacteria-biochar-Hermetia illucens interaction” conversion system and explore the effects of combination strategies, such as substrate ratio, density of H. illucens larvae, biochar, and functional microbes, on the system for converting chlortetracycline fermentation residues of H. illucens. 【Methods】H. illucens larvae were reared to the 3rd instar with wheat bran. Then, different mass ratios of chlortetracycline fermentation residues to wheat straw (chlortetracycline fermentation residues∶ wheat straw=0∶1, 1∶2, 1∶4, 1∶8, 1∶12 and 1∶20), larval densities (larval number∶ substrate mass=0.6∶1, 0.8∶1, 1∶1, 2∶1, 4∶1, 6∶1, 8∶1 and 10∶1), biochar addition (0, 30, 60, 90, 120, 150 and 180 g/kg), functional bacteria (Providencia stuartii TX2, Klebsiella pneumoniae TX1, and Bacillus velezensis EEAM 10B), and mixed addition groups were set up. The growth and development indices of H. illucens larvae (body weight, body length, and body width), substrate conversion indices (substrate consumption rate and substrate conversion rate), and chlortetracycline removal rate in the substrate were measured. 【Results】In the optimal “bacteria-biochar-H. illucens interaction” conversion system for chlortetracycline fermentation residues, with a chlortetracycline fermentation residue to straw ratio of 1∶4, a larval density of 1∶4, a biochar addition ratio of 120 g/kg, and the presence of P. stuartii TX2, the larval weight, length and width of H. illucens reached 0.17 g/individual, 18.27 mm and 4.83 mm, respectively. Additionally, in the optimal “bacteria-biochar-H. illucens interaction” conversion system, the substrate consumption rate and substrate conversion rate reached 34.04% and 29.50%, respectively, while the chlortetracycline removal rate in the substrate increased to 96.23%. 【Conclusion】Through the optimization of the highly efficient “bacteria-biochar-H. illucens interaction” conversion system for antibiotic fermentation residues, two types of organic solid waste were converted into high-value insect protein, while the chlortetracycline removal rate in the substrate was improved.

Key words: Hermetia illucens, chlortetracycline fermentation residue, wheat straw, biochar, functional microbes