発泡した活性汚泥から分離されたグラム陰性糸状性細菌

抄録

A Gram-negative filamentous bacterium was newly isolated from the foaming activated sludge in a municipal sewage treatment plant. The bacterium formed the necklace-like chains underin situcondition or acetate added cultivation. It predominated in the foaming materials up to 90% of total viablecounts. It could be successfully harvested by adding agar extract to be subjected to quinone analysis. Its major quinone consisted of Q-9 and Q-8, the ratio of 4 to 1.It utilized acetate and polypeptone as carbon and nitrogen sources, respectively. The bacterium could reduce nitrate to nitrite. However, it could not be related to in situ accumulation of nitrite up to 6mg/l. The predominance of such a unusual bacterium, far from normal activated sludge bacterial community, is thought to be indicated that the condition of aeration tanks is getting unstable fluctuating state.Therefore, such arare bacterium would be occupied an altermative ecological niche in the activated sludge.