Isolation, identification and characteristics of a sucrose-preferred heterotrophic nitrification-aerobic denitrification bacterium strain from seawater

At present, high nitrogen content in farming tailwater and the inability to achieve standard discharge is a common problem, so there is an urgent need to find a cost effective and safe solution. A sucrose preference strain XH1 with heterotrophic nitrification-aerobic denitrification function was isolated from the coastal zone of the Yellow River Delta. Morphological observation and 16S rDNA homology analysis showed that the strain belonged to Enterococcus sp.. The experiments on influencing factor analysis showed that this strain had the highest TN removal rate of 78.8% for nitrification reaction and 80.8% for denitrification reaction when sucrose used as the carbon source, C/N=15, T=25 ℃ and salinity=35 in the medium. Strain XH1 could grow well and conduct denitrification reactions when C/N=5～30, salinity=5～55, T=15 ℃～35 ℃ and sucrose was used as the only carbon source in the medium. Sucrose was widely used in aquaculture because of its low cost. The results significantly expanded the scope of application of the strain XH1, and laid the foundation for its application in the treatment of high nitrogen aquaculture tailwater in practice.