Aerobic Cr(VI) Reduction by an Indigenous Soil Isolate Bacillus thuringiensis BRC-ZYR2

摘要: Abstract Chromium (Cr) may cause losses in the yield of field plant, which is one favorite habitats Bacillus thuringiensis (Bt). The purposes our study were to assess Cr(VI)-resistance and Cr(VI)-reducing abilities an indigenous soil isolate Bt determine factors governing Cr(VI) reduction. Towards this end a novel dichromate-reducing BRC-ZYR2, characterized with insecticidal crystal proteins (ICPs), was isolated from uranium deposit. Minimum inhibitory concentrations (MICs) determined by broth dilution method total Cr supernatant quantified colorimetrically using 1,5-diphenylcarbazide (DPC) reagent mixture sulfuric-nitric acids, respectively. contained five ICP genes ( cry1Ba, cry1Bb, cry1Be/cry1Bf, cry9Ca cry9Da ) exhibited high level resistance MICs 150 mg L −1 at pH 7.0 30 °C, 500 under optimal conditions (pH 9.0 40 °C). concentration similar initial condition, suggesting that essential removal dependent on Under conditions, 25 75 significantly decreased 24 h after incubation. Addition Mn 2+ , Co Mo Cu activated Bt-mediated reduction, while Zn Ni glucose found inhibit Our results indicated could be promising biopesticide potential for both insect biocontrol bioremediation field.