Abstract
An enrichment culture of soil ammonia oxidizing bacteria was filtrated through a 2.0μm membrane filter (Nuclepore) to remove soil particles and filtrates were transferred to a fresh medium for the enrichment. An addition of antibiotics such as tetracycline and ampicillin and filtration through a 0.8μm membrane filter were useful to decrease contamitants. Using a higher enrichment culture colonies of ammonia oxidizing bacteria (300-600μm in diameter) were obtained on GELRITE-solidified plates. Cells picked up from the colony by means of capillary tubes were grown on a liquid media and produced nitrite from ammonia but did not show heterotrophic growth. Such isolation of ammonia oxidizing bacteria in culture using GELRITE-solidified plate was accomplished with comparative ease.
