Identification of a novel anaerobic dephosphorization bacterial strain and its activity in phosphate removal under anaerobic condition

This study was conducted by using the sludge from the concentration pond as an inoculum to enrich the functional bacteria which might reduce phosphate into PH3 in a continuous stirred flow incubating reactor. The classificational status of this functional bacterium was also studied in a static state reactor under anaerobic condition according to its morphological, physiological, biochemical properties, and the analysis of its 16S rDNA gene sequence. The results showed that this bacterium might be a novel heterotrophic dephosphorization bacterium under anaerobic condition. There was 98.7% homology of its 16S rDNA gene sequence to Pseudochrobactrum saccharolyticum. The optimal carbon and nitrogen sources for this bacterium were glucose and sodium acetate, and peptone and ammonium chloride, respectively. However, cellulose and nitrate was unsuitable as carbon and nitrogen sources. The addition of organic phosphate was helpful but not significant to the activity of this bacterium. The best initial pH value of the reaction was 6-7, and the optimum temperature range was 30-35C. The growth of this bacterium was inhibited when the temperature was 4C, and its activity decreased when the temperature was above 35C. There was no significant effect on biological dephosphorization by means of addition of reducer-sufide while incubating in the reactor under anaerobic condition.