Rapid elimination of butralin residues on tobacco, in water and soils by newly isolated Bacillus sp. LY05

Hazardous butralin residues in agricultural products and environments have been proved to be potentially toxic to insects, hydrobios, mammals, and humans. A new butralin-degrading strain LY05 was isolated from butralin-contaminated soils and identified as Bacillus sp. LY05 was immobilized using a blended carrier (charcoal, alginate, and chitosan), which exhibited superior biodegradation, storage and reutilization abilities. Strain LY05 could effectively translate butralin into two simple products through sequential nitroreduction and dealkylation, which was different from the metabolic pathways and mechanisms of the other single strains reported previously. Foliar application of free LY05 decreased the half-life of butralin sprayed on tobacco leaves at the recommended and double dosages by 2.39- and 2.94- fold compared to natural dissipation, respectively. In a simulated flow reactor, the total average degradation efficiency of butralin by immobilized LY05 was 85.43 % at influent concentrations of 50, 75 and 100 mg/L within 30 days (d). Compared to free LY05 and control, immobilized LY05 decreased the half-life of butralin sprayed to soils at the recommended and double dosages by 2.50- to 2.87- fold and 11.65- to 12.36- fold, respectively. This study indicates that Bacillus sp. LY05 can be used as a feasible in situ bioeliminator for butralin residues on tobacco crops, as well as in water and soil environments. [Display omitted] •Bacillus sp. LY05 was a newly efficient degrader of butralin.•Strain LY05 could effectively degrade butralin to two simple products.•Charcoal from waste tobacco stems was recycled as an immobilized material.•Immobilization improved biodegradability, stability and reusability of LY05.•Free or immobilized LY05 rapidly eliminated butralin on tobacco, in water and soil.