Biotechnology Bulletin ›› 2022, Vol. 38 ›› Issue (10): 226-234.doi: 10.13560/j.cnki.biotech.bull.1985.2021-1084

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Biosafety and Nitrogen Removal Performance of a Safe and Efficient Aerobic Denitrifying Pseudomonas stutzeri DZ11

ZHAO Yang(), SUN Hui-ming, LIN Hao-peng, LUO Ping-ting, ZHU Ya-ting, CHEN Qiong-hua, SHU Hu()   

  1. School of Life Science,Guangzhou University,Guangzhou 510006
  • Received:2021-08-07 Online:2022-10-26 Published:2022-11-11
  • Contact: SHU Hu E-mail:627507619@qq.com;shuhuhu001@126.com

Abstract:

The aerobic denitrifying bacteria separated and screened from the bottom sludge and sewage of the aquaculture farm in Minzhong town,Zhongshan city,were studied,aiming to lay the foundation for the development of the denitrification process of aquaculture wastewater. The high-performance bacterium DZ11 was selected from the samples,and its morphological observation,physiological and biochemical determination and 16S rDNA gene sequence analysis were performed to determine the species of the strain. Besides,drug susceptibility test and biological safety test were conducted to confirm the safety of strains. Then the influences of carbon source types,temperature,pH value and carbon-nitrogen ratio on the nitrogen removal efficiency were studied to improve the denitrification efficiency of strains’ performance. The identification results showed that the strain DZ11 was identified as Pseudomonas stutzeri and named Pseudomonas stutzeri DZ11. Drug susceptibility test and biological safety test demonstrated that the strain had no obvious drug resistance and had high biological safety. The result of single factor optimization is that the optimal carbon source of strain DZ11 was sodium citrate,the optimal temperature was 30.0-35.0℃,the optimal pH was 7,and the optimal C/N was in the range of 10-20. When NH4-N,NO3-N,and NO2-N were the only substrates,the transformation rates were 84.39%,99.0% and 97.65%,respectively,indicating that the strain had a good denitrification effect. In sum,the strain DZ11 has high biological properties and high-efficiency denitrification performance,and has great application potential in the denitrification process of aquaculture wastewater.

Key words: aerobic denitrifying bacterium, Pseudomonas, biological removal of nitrogen, bio-safety