ヒ素除去に有用な微生物の探索 Screening and characterization of useful microorganisms to arsenic removal
Microorganisms were isolated from soil and their arsenic removal abilities were evaluated. Seven out of the 100 isolated strains showed more than 20% arsenic removal. Time courses of arsenic removal and cell growth were investigated in three of these isolated strains. Although the growth rates were different, the dependence of arsenic removal on cell growth was similar in three strains (A-84, 88, 89). Strain A-89 showed highest arsenic removal rate of 63% after first day. Strain A-88 was best in terms of the amount of arsenic absorbed per one gram of dry cell, at 0.46 mg/g・cell after first day, although it showed the worst cell growth among the three strains. Strain A-89 was further examined to study the influence of arsenic concentration on arsenic removal and growth. The arsenic removal with 0.2 ppm and 1.0 ppm arsenic concentration in the culture solution was similar with a maximum of about 60% after 24 hours.### With 10.0 ppm arsenic concentration in the culture solution, almost no cell growth was observed and arsenic in the culture solution was not removed. The forms of arsenic hardly changed in any of the culture solutions.