Application of Bacillus sp. NITD 19 for Utilization of Cyanide …
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2.2 Lethal Dose Analysis
Test stain was grown on minimal media with varying concentration of cyanide from
20–100 mg/L with inoculum load 2% at pH 7. The culture was kept in BOD shaker
(Modern Equipment, M/s Atlanta Drugs and Chemicals, India) at temperature 37 °C
and shaking speed 120 rpm under aseptic condition for 72 h. Samples were collected
after incubation period. The samples were centrifuged at 5000 rpm for 15 min.
Supernatant was analyzed with selective ion meter (Thermo scientific, Orion Dual
Star, pH/ISE) for measuring residual cyanide concentration. Pellet was washed twice
with deionized water and kept for drying at 65 ± 2 °C overnight for getting cell
biomass concentration.
2.3 One Factor at a Time (OFAT) Analysis and Time
Variation of Cyanide Removal
In order to know the effects of the different parameters like pH, inoculum load,
temperature, and initial cyanide concentration on removal of cyanide, OFAT study
was performed by varying the pH (6–10), inoculum load (1–4%), temperature (25–
37 °C), and initial concentration (20–100 mg/L) individually in a judicial manner
(Upendar et al. 2018). Test strain was grown in minimal media for 72 h at a particular operating condition and samples were collected and analyzed for cell biomass
concentration and residual cyanide concentration.
After assessing suitable operating conditions corresponding to maximum cyanide
removal, time variation study was performed. Test strain was grown in cyanide loaded
minimal media at pH 8 with inoculum load 4%, and at temperature 37 °C for 72 h.
Samples were collected after every two hours intervals and were analyzed for residual
cyanide concentration and cell biomass content.
2.4 Characterization of Cell Biomass
Fourier Transform Infrared spectroscopy (FTIR) study of both treated and untreated
dry biomass of test strain was done using Fourier Transform Infrared spectrophotometer (Instrument Model: NEXUS-870).
243
2.2 Lethal Dose Analysis
Test stain was grown on minimal media with varying concentration of cyanide from
20–100 mg/L with inoculum load 2% at pH 7. The culture was kept in BOD shaker
(Modern Equipment, M/s Atlanta Drugs and Chemicals, India) at temperature 37 °C
and shaking speed 120 rpm under aseptic condition for 72 h. Samples were collected
after incubation period. The samples were centrifuged at 5000 rpm for 15 min.
Supernatant was analyzed with selective ion meter (Thermo scientific, Orion Dual
Star, pH/ISE) for measuring residual cyanide concentration. Pellet was washed twice
with deionized water and kept for drying at 65 ± 2 °C overnight for getting cell
biomass concentration.
2.3 One Factor at a Time (OFAT) Analysis and Time
Variation of Cyanide Removal
In order to know the effects of the different parameters like pH, inoculum load,
temperature, and initial cyanide concentration on removal of cyanide, OFAT study
was performed by varying the pH (6–10), inoculum load (1–4%), temperature (25–
37 °C), and initial concentration (20–100 mg/L) individually in a judicial manner
(Upendar et al. 2018). Test strain was grown in minimal media for 72 h at a particular operating condition and samples were collected and analyzed for cell biomass
concentration and residual cyanide concentration.
After assessing suitable operating conditions corresponding to maximum cyanide
removal, time variation study was performed. Test strain was grown in cyanide loaded
minimal media at pH 8 with inoculum load 4%, and at temperature 37 °C for 72 h.
Samples were collected after every two hours intervals and were analyzed for residual
cyanide concentration and cell biomass content.
2.4 Characterization of Cell Biomass
Fourier Transform Infrared spectroscopy (FTIR) study of both treated and untreated
dry biomass of test strain was done using Fourier Transform Infrared spectrophotometer (Instrument Model: NEXUS-870).