A bacterial isolate of N43 was grown in nutrient broth on a rotary shaker at 30 °C and 170 rpm for 24 h. The suspension was centrifuged in sterile 50-ml plastic tubes at 6000 rpm for 10 min. The pellets were re-suspended in sterile distilled water to obtain a final concentration of 108 cells ml−1 (OD = 0.5) at 600 nm, which was measured with the viable plate count and optical density methods