Isolation and characterization of cyromazine-degrading bacteria from soil and its application in bioconversion by black soldier fly

Cyromazine, a widely used insect growth regulator, accumulates in livestock manure and poses risks to beneficial insects such as black soldier fly larvae (BSFL) during waste bioconversion. This study isolated two bacterial strains capable of degrading cyromazine, Bacillus subtilis CYR1 (CYR1) and Bacillus velezensis CYR2 (CYR2), from contaminated chicken manure. Both strains demonstrated significant degradation efficiency via hydrolysis of cyromazine to cyanuric acid, a less toxic metabolite. However, in chicken manure systems, degradation efficiency reached a plateau at approximately 20%, likely due to preferential utilization of alternative nitrogen sources and inherent metabolic constraints. These findings highlight the potential of microbial remediation to mitigate cyromazine contamination while underscoring the need for strain optimization and comprehensive ecotoxicological assessments.