Isolation and culturing of a most common anaerobic ciliate, Metopus sp.

The study includes isolation of anaerobic ciliate, Metopus sp. from an anaerobic reactor and development of its monoculture under laboratory conditions. Separation by centrifugation followed by micromanipulatory isolation resulted in obtaining pure Metopus culture with less bacterial contamination. The isolated Metopus sp. had the mean dimensions of 32×123 μm with the generation time of 53 h. Among the different basal media tried, the ciliate mineral medium (CMV) with 1% wheat powder suspension was the most suitable one for Metopus growth. The temperature and pH ranges, for the best growth of Metopus, were 30–35 °C and 6–7, respectively. Higher concentrations of volatile fatty acids (VFA) such as acetate, butyrate and propionate had adverse effect on Metopus growth and prevented its growth beyond 0.05 M concentration. Maximum COD removal was in CMV medium by the growth of anaerobic Metopus sp.