一株高效好氧反硝化菌的分离及特性

Isolation and Characterization of a High Efficiency Aerobic Denitrifier

摘要:

利用富集培养的方法从南昌市郊某养鱼塘采样分离出22株反硝化细菌, 其中8株反硝化率较高, 从中选择一株效果最好的作为研究对象, 命名为HS-N62, 对其生长特性进行了深入研究。结果表明: 硝酸盐氮初始浓度为140 mg/L, 菌株HS-N62在12 h内对硝酸盐氮的去除率可达96%, 而且没有亚硝酸盐氮的积累。该菌最适生长温度范围为30°C?37°C, 最适生长pH范围6.0?8.0, 最适C/N比为10 : 1, 并能利用多种碳源生长。运用正交试验探讨了该菌株最适的反硝化条件。反硝化菌株HS-N62还具有较好的除磷能力, 12 h除磷率达到67.7% (初始磷酸盐浓度57 mg/L)。通过形态学特性和生理生化分析以及16S rRNA基因序列分析, 菌株HS-N62与Pseudomonas sp.亲缘关系最为接近, 相似性达99%, 初步鉴定该菌为假单胞菌属(Pseudomonas sp.)。

Abstract:

Twenty two bacterial strains with a capacity of denitrification were isolated from fish pond, of which eight strains have the high rate of denitrification while one strain named HS-N62 has the strongest effect of denitrification. The results showed that the denitrifying rate of strain HS-N62 reached 96% in 12 hours with initial nitrate nitrogen concentration of 140 mg/L and no nitrite nitrogen accumulation. The growth rate and characteristics of HS-N62 were further studied, and the results showed that the optimum growth temperature ranged from 30°C to 37°C, pH value from 6.0 to 8.0 and the optimal C/N ratio 10:1. Meanwhile strain HS-N62 could utilize a variety of carbon sources for growth. The most suitable denitrification condition for strain HS-N62 was confirmed by using a series of the orthogonal test. This denitrifying strain HS-N62 also has good ability of phosphorus removal, and the removal rate within 12 hours was up to 67.7% (at initial phosphate concentration 57 mg/L). Strain HS-N62 showed 99% 16S rRNA gene sequence similarity to many Pseudomonas strains. Based on the morphological characteristics, physiological and biochemical characteristics, the strain HS-N62 was identified as Pseudomonas sp.