Heterotrophic bacteria were collected from soils in several areas in Suwon, Korea. Among the screened bacteria, one bacterium was gram-negative, rod-shaped, catalase-positive, motile, and it showed a positive utilization for citrate, mannitol, sucrose, fructose, and trehalose as energy source. On th...
Heterotrophic bacteria were collected from soils in several areas in Suwon, Korea. Among the screened bacteria, one bacterium was gram-negative, rod-shaped, catalase-positive, motile, and it showed a positive utilization for citrate, mannitol, sucrose, fructose, and trehalose as energy source. On the basis of its biochemical characteristics it was identified as Burkholderia(formely Pseudomonas) cepacia. The optimum pH and temperature for the growth of the bacterium were 7.0 and 30℃, respectively. The pH range for the growth of Burkholderia (Pseudomonas) cepacia was very broad and 5.0-8.0. The cell growth was inhibited by acidification due to the accumulated sulfate in liquid medium. The growth rate of the bacterium in thiosulfate medium with yeast extract was 0.15 hr-1 and generation time was 4.6 hr. The cell productivity was 8.05 mg/L·h and the isolate grew logarithmically up to 21 hr. The maximum sulfur oxidation rate was 0.18 g-S/L·h. The thiosulfate oxidation rate was inhibited by a substrate thiosulfate , it's concentration was higher than 0.12M. The effect of glucose and yeast extract on the growth and the sulfur oxidation rate of B.cepacia was investigated. Both growth rate and sulfur oxidation rate of B.cepacia was enhanced about 1.5 times with the addition of 0.2% yeast extract. The removal efficiency of hydrogen sulfide by the isolated bacterium was investigated by immobilized B. cepacia with 4% Ca-alginate. The initial pH of bead and temperature for the biofilter were 6.0 and 25℃, respectively. The removal rate of H2S was 65% at the initial inlet gas, however it was decreased to 0% after 16hrs without microorganisms to the immobilized bead. Therefore, 16hrs reaction is considered to be affinity reaction of only alginate. The removal rate was increased until 8hrs by affinity alginate with the variation of input concentration of H2S to the Biofilter and space velocity, 2-70ppm and 53-119h-1, respectively after inoculation B.cepacia to the immobilized bead. And its rate was increased after 16hrs of adaptation time. The maximum removal rate of H2S was calculated from the Hanes-Wolf plot at various flow rates and the rate was 6.25g ? cm-3 ? h-1 when 12L/h of flow rate was supplied. The H2S removal efficiency was decreased with the increase of H2S concentration and of flow rate of gas. Its efficiency was not showed much difference at the flow rate of 12L/h and 15L/h, but the removal rate was decreased to 60% with the increase of flow rate to 27L/h. The removal capacity was doubled when the flow rate of gas was increased from 12L/h to 27L/h. Therefore, the flow rate of gas has very close relationship with both the removal rate and removal capacity between 10 to 30 ppm of H2S concentration. The removal efficiency and capacity showed reverse results at high flow rate. This phenomenon was caused by mass transfer(restriction of dispersion), not by restriction of enzyme activity of microbe. Therefore, it is required to increase the volume of bead to reach optimal removal capacity or to decrease inlet flow rate of high concentration of H2S to the inside of Biofilter.
Heterotrophic bacteria were collected from soils in several areas in Suwon, Korea. Among the screened bacteria, one bacterium was gram-negative, rod-shaped, catalase-positive, motile, and it showed a positive utilization for citrate, mannitol, sucrose, fructose, and trehalose as energy source. On the basis of its biochemical characteristics it was identified as Burkholderia(formely Pseudomonas) cepacia. The optimum pH and temperature for the growth of the bacterium were 7.0 and 30℃, respectively. The pH range for the growth of Burkholderia (Pseudomonas) cepacia was very broad and 5.0-8.0. The cell growth was inhibited by acidification due to the accumulated sulfate in liquid medium. The growth rate of the bacterium in thiosulfate medium with yeast extract was 0.15 hr-1 and generation time was 4.6 hr. The cell productivity was 8.05 mg/L·h and the isolate grew logarithmically up to 21 hr. The maximum sulfur oxidation rate was 0.18 g-S/L·h. The thiosulfate oxidation rate was inhibited by a substrate thiosulfate , it's concentration was higher than 0.12M. The effect of glucose and yeast extract on the growth and the sulfur oxidation rate of B.cepacia was investigated. Both growth rate and sulfur oxidation rate of B.cepacia was enhanced about 1.5 times with the addition of 0.2% yeast extract. The removal efficiency of hydrogen sulfide by the isolated bacterium was investigated by immobilized B. cepacia with 4% Ca-alginate. The initial pH of bead and temperature for the biofilter were 6.0 and 25℃, respectively. The removal rate of H2S was 65% at the initial inlet gas, however it was decreased to 0% after 16hrs without microorganisms to the immobilized bead. Therefore, 16hrs reaction is considered to be affinity reaction of only alginate. The removal rate was increased until 8hrs by affinity alginate with the variation of input concentration of H2S to the Biofilter and space velocity, 2-70ppm and 53-119h-1, respectively after inoculation B.cepacia to the immobilized bead. And its rate was increased after 16hrs of adaptation time. The maximum removal rate of H2S was calculated from the Hanes-Wolf plot at various flow rates and the rate was 6.25g ? cm-3 ? h-1 when 12L/h of flow rate was supplied. The H2S removal efficiency was decreased with the increase of H2S concentration and of flow rate of gas. Its efficiency was not showed much difference at the flow rate of 12L/h and 15L/h, but the removal rate was decreased to 60% with the increase of flow rate to 27L/h. The removal capacity was doubled when the flow rate of gas was increased from 12L/h to 27L/h. Therefore, the flow rate of gas has very close relationship with both the removal rate and removal capacity between 10 to 30 ppm of H2S concentration. The removal efficiency and capacity showed reverse results at high flow rate. This phenomenon was caused by mass transfer(restriction of dispersion), not by restriction of enzyme activity of microbe. Therefore, it is required to increase the volume of bead to reach optimal removal capacity or to decrease inlet flow rate of high concentration of H2S to the inside of Biofilter.
주제어
#황화 수소 미생물 hydrogen sulfide
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