Identification and characterization of a hypothermia nitrite bacterium Pseudomonas tolaasii Y-11

Abstract:

Abstract:［Objective］Denitrifying bacteria play an important role in the biological nitrogen removal process．However，there are few studies about hypothermia nitrite denitrifying bacteria．We isolated a hypothermia and aerobic nitritedenitrifying bacterium (named as Y-11) from the long-term flooded paddy soil．Aims of this paper were to clarify the phylogeny and denitrifying characteristics of strain Y-11．［Methods］ Morphological observation，specific phospholipid fatty acid and 16S rＲNA analysis were employed to identify strain Y-11． Denitrification characteristics of strain Y-11，such as temperature，shaking speed，initial pH and carbon source were investigated by using shaking culture in Erlenmeyer flask．［Results］ Strain Y-11 with high removal efficiency of nitrite and total nitrogen was identified as Pseudomonas tolaasii． The optimum conditions of Y-11effectively removing nitrite nitrogen and total nitrogen were: initial pH7.0; 15 ℃; shaking speed 200 r/min; inoculum size 1.5×108 CFU per 100 mL medium; sodium acetate as carbon source; and nitrite nitrogen 10 mg/L．Strain Y-11 can remove nitrite nitrogen and total nitrogen up to 100% and 61.28% within 48 h.［Conclusion］Strain Y-11 was identified as Pseudomonas tolaasii with its potential nitrite polluted water treatment during early winter and late spring．

Key words:Keywords: nitrite denitrifying bacterium，hypothermia，isolation and identification，Pseudomonas tolaasii