Experimental study on improving nitrogen removal efficiency of denitrify bacteria by protoplast fusion

摘要

Three bacteria named A1, B1 and C1 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-A1, K-B1 and K-C1. 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 CO and CO{sub}2 were obtained. CO was identified to be Bacillus, and CO{sub}2 was Nitosococcus. By comparing with their parent strains, the nitrogen removal efficiency of CO was 27.4% higher than C1, and the efficiency of CO{sub}2 did not change obviously.