耐盐产酸克雷伯氏菌(Klebsiella oxytoca) WM27的特征、脱氮性能及固定化

Characteristics, denitrification performance, and immobilization of Klebsiella oxytoca WM27

摘要:

【背景】好氧反硝化细菌在水产养殖尾水处理中显现出广泛的应用潜力。然而，大多数好氧反硝化细菌在高盐环境中的脱氮性能有限。【目的】筛选出耐盐好氧反硝化细菌，并对其脱氮性能进行评估。【方法】从养殖池塘底泥中富集筛选出1株新型高效好氧反硝化细菌，通过16S rRNA基因测序及生理生化试验鉴定菌种；采用动物试验和药敏试验对分离菌进行毒力和耐药性检测，设置不同的环境因素探寻最佳脱氮条件并进行优化，利用固定化技术提高其应用能力。【结果】经鉴定，菌株WM27为产酸克雷伯氏菌(Klebsiella oxytoca)，有较高的抗生素敏感性及较好的生物安全性。以琥珀酸钠为碳源，菌株WM27在C/N=10、pH 7.0、温度25 ℃的条件下具有较强的脱氮能力，对总氮(total nitrogen, TN)、NH₄⁺-N、NO₂^--N和NO₃^--N的去除率可达到90%以上。该菌株在3%的盐度环境下具有良好的脱氮能力，TN、NH₄⁺-N、NO₂^--N的去除率仍有88%以上；经固定化菌株WM27的脱氮处理，NH₄⁺-N、NO₂^--N和NO₃^--N 48 h的降解效果可分别达到98.62%-99.46%、98.26%-100%和98.34%-100%。【结论】菌株WM27是一株耐盐、安全且高效的好氧反硝化细菌，在高盐养殖尾水处理中具有潜在的应用价值。

Abstract:

[Background] Aerobic denitrifying bacteria have shown a wide range of application potential in the treatment of aquaculture tail water. However, most aerobic denitrifying bacteria have limited denitrification performance in high-salt environments. [Objective] To screen out salt-tolerant aerobic denitrifying bacteria and evaluate their denitrification performance. [Methods] A novel, efficient aerobic denitrifying bacterial strain was selected from the bottom sediment of the aquaculture pond, and the strain was identified by 16S rRNA sequencing and physiological and biochemical tests. Animal tests and antimicrobial susceptibility tests were conducted to examine the virulence and antibiotic resistance of the isolate. Environmental factors affecting the denitrification performance were optimized, and the immobilization technology was employed to improve its application. [Results] Strain WM27 was identified as Klebsiella oxytoca, which had high antibiotic sensitivity and good biosafety. With sodium succinate as the carbon source, strain WM27 had strong denitrification performance under the conditions of C/N=10, pH 7.0, and 25 °C, with the removal rates of TN, NH₄⁺-N, NO₂^--N, and NO₃^--N reaching more than 90%. The strain had good denitrification ability at 3%, with the removal rates of TN, NH₄⁺-N, and NO₂^--N still more than 88%. The degradation effects of NH₄⁺-N, NO₂^--N, and NO₃^--N for 48 h were 98.62%-99.46%, 98.26%-100%, and 98.34%-100%, respectively. [Conclusion] Strain WM27 is a salt-tolerant, safe, and efficient aerobic denitrifying bacterium, demonstrating a potential application value in the treatment of high-salt aquaculture tail water.