2.4. Screening of bacterial isolates for growth and fipronil degradation in liquid
medium
For studies on relative growth of different bacterial isolates and fipronil
degradation capacities, individual bacterial isolates were allowed to grow in liquid
Dorn's medium supplemented with fipronil at 2871 1C on shaker at 150 rpm before
estimation of the bacterial growth and analysis of fipronil degradation. For this
purpose, 50 ml of Dorn's broth in a 250 ml Erlenmeyer flask was supplemented with
fipronil (50 mg ml−1
) and inoculated with one ml of overnight grown culture of the
respective bacterial isolate in 5 ml of Luria broth. The inoculated medium was
incubated at 28 1C on an orbital shaker (120 rpm) for 14 days.
Estimation of bacterial growth was measured as increase in optical density
(OD600). For this purpose, bacterial cell culture (5 ml) drawn at regular intervals was
centrifuged (600 rpm, 5 min). The collected cell mass in the pellet was suspended in
5 ml of distilled water and its optical density was measured in a spectrophotometer
using water as control blank.