耐冷亚硝酸盐型反硝化菌Pseudomonas tolaasii Y-11的鉴定及其脱氮特性

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

摘要:

摘要:【目的】反硝化细菌在生物脱氮中具有重要作用，而耐冷亚硝酸盐型反硝化细菌研究较少，本文从长期淹水的冬水田泥土分离获得一株耐冷高效去除亚硝酸盐氮和总氮的好氧反硝化细菌Y-11，明确其分类地位以及除氮特性，以期为后续利用该菌在初冬到春末处理亚硝酸盐水体污染奠定基础。【方法】通过形态学特征、特异性磷脂脂肪酸以及16S rRNA基因测序分析对该菌株进行鉴定;在好氧条件下以亚硝酸钠为唯一氮源，分别研究不同初始温度、转速、pH、碳源、接种量以及亚硝酸盐氮浓度对该菌去除亚硝酸盐氮和总氮的影响，确定最适降解条件。【结果】分离得到的菌株Y-11，经鉴定归于托拉斯假单胞菌(Pseudomonas tolaasii);在国内外尚无该种菌具有反硝化作用的报道，是对亚硝酸盐型反硝化细菌的进一步补充。Y-11菌株的最适脱氮条件为15 ℃，200 r/min，pH7.0，100 mL反硝化培养基中最适接种量为1.5×108 CFU，最佳碳源为乙酸 钠，亚硝酸盐氮为10 mg/L;以乙酸钠为电子供体，15 ℃、初始pH为7.2、150 r/min 振荡培养，48 h对亚硝酸盐氮和总氮的去除率分别为100%和61.28%。【结论】Y-11是一株具有较高反硝化能力的托拉斯假单胞菌，能高效地去除亚硝酸盐氮和总氮，其最适温度是15 ℃左右，是一株耐冷反硝化细菌。

关键词:关键词:亚硝酸盐型反硝化细菌，耐冷，分离与鉴定，托拉斯假单胞菌

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