The microorganism for ammonia gas removal was isolated from composting product. This was identified as Brevundimonas diminuta by morphological, biochemical characteristics study and 16S rDNA sequence analysis. Optimal incubation temperature for cell growth and oxidizing ability of NH4-N was 30oC and optimal initial pH was 7. Glucose affected the growth of cell and the removal of NH4+. The growth rate of the isolates were increased when grown in the presence of 0.05-1%(w/v) glucose in the selective medium and further increases in glucose concentration to 2% caused significant decreases in the cell growth and oxidizing ability of NH4+.