Integrative genome sequencing and experimental validation uncover the biopesticidal and bioremediation potential of a wastewater-derived Bacillus thuringiensis strain

: The valorization of industrial wastewater through biotechnological approaches represents a promising strategy for sustainable, cost-effective bioproduction and environmental pollution control. Three industrial wastewaters from a pasta manufacturing plant, specifically the complex industrial process effluent (M1), the final treated effluent (M2), and the extrusion die rinsing wastewater (M3), were evaluated as sustainable feedstocks for Bacillus thuringiensis ( Bt ) isolation and production. Interestingly, a newly Bt kurstaki strain, designated Bt 1, was isolated from these effluents. The use of nutrient-rich medium M1 for Bt 1 cultivation led to a nearly seven-fold increase in toxin yield compared to the glucose-based medium, reaching 109 mg 10 -10 spores instead of 15.69 mg 10 -10 spores. Furthermore, Bt 1 cells grown in M1 exhibited the highest insecticidal activity against Ephestia kuehniella and Ectomyelois ceratoniae , outperforming both the reference strain HD1 and the commercial formulation DELFIN. Cultivation of the newly isolated strain Bt 1 under non-sterile conditions further demonstrated the suitability of the alternative medium M1 for biopesticide production and bioremediation, achieving a δ-endotoxin concentration of 420.15 mg L -1 and removal efficiencies of 92.66% for Zn 2+ , 64.28% for Fe 2+ , 59% for Cu 2+ , and 100% for Mn 2+ . Genomic annotation proved evidence of the presence of multiple cry genes, as well as genes encoding hydrolytic enzymes, virulence factors, and pathways related to organic matter degradation, persistence, host interaction, and heavy metals uptake, highlighting the Bt 1 efficiency as a prominent agent for eco-friendly, sustainable agriculture, and bioremediation in line with circular economy principles.