Experimental Study on Improving Nitrogen Removal Efficiency of Denitrify Bacteria by Protoplast Fusion

Three bacteria named Al, Bl and CI were isolated from activated sludge in Zhuankou "863" Experimental Base by limiting dilution and flat crossed separation, which had high nitrogen removal efficiency.Through UV-irradiaion, three single resisitance mutants were obtained, which named K-Al, K-Bl and K-Cl. Then these three mutants were used as parent strains to process protoplast fusion and the fusants were selected by medium containing two kinds of antibiotics. Two fusants named CO1 and CO2 were obtained. CO1 was identified to be Bacillus, and CO2 was Nitosococcus. By comparing with their parent strains ,the nitrogen removal efficiency of CO1 was 27.4% higher than Cl, and the efficiency of CO2 did not change obviously.