Abstract: In order to obtain a heterotrophic nitrification-aerobic denitrification strain,a yeast with heterotrophic nitrification-aerobic denitrification ability was isolated and screened from the sludge of aquaculture pond,named as DW-1. The strain was identified as Diutina rugosa by morphological observation and 26S rDNA sequence analysis. The effects of carbon sources,C/N,initial pH value,cultural temperature and shaking speed on the nitrogen removal performance of strain DW-1 were preliminarily discussed with ammonia nitrogen as the sole nitrogen source. The results showed that the degradation rate of ammonia nitrogen and removal rate of total nitrogen by strain DW-1 were 94.94% and 48.69% respectively,under the conditions of sodium acetate as the sole carbon source,C/N 25,pH 6.0,appropriate culture temperature 32℃ and rotate speed 170 r/min;while the accumulation of nitrite nitrogen in the whole process was only 0.067 mg/L. The heterotrophic nitrification-aerobic denitrification performance of D. rugosa DW-1 indicates that it has a promising application prospect in the treatment of nitrogen-containing wastewater.

Key words: heterotrophic nitrification, aerobic denitrification, Diutina rugosa, denitrification characteristics