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不同C/N对生物絮凝硝化作用强度及微生物群落的影响

Effects of Different C/N on Bio-flocculation Nitrification Intensity and Microbial Community

  • 摘要: 为了探究不同C/N (投入的总碳质量/投入的总氮质量)对生物絮凝硝化作用强度及微生物群落的影响,设置C/N为10:1、15:1、20:1、25:1、30:1进行相关研究。结果发现:C/N为10:1和15:1两组NO3-的积累量显著高于其他组的(P<0.05),且C/N为10∶1和15∶1两组NO3-的积累量存在显著性差异(P<0.05)。5个处理组的氧化还原电位(ORP)在实验第一天迅速下降到负值,但5组间ORP变化均无显著性差异(P>0.05)。从节约碳源的角度考虑,在第一批次实验筛选出的差异组间,即在C/N为10:1和C/N为15:1之间,设置C/N为10:1、11:1、12:1、13:1和14:1,对照组不添加葡萄糖。结果显示,随着C/N的升高,各处理组NO3-的积累量逐渐下降。不添加碳源组NO3-的积累量明显高于其他组的(P>0.05)。不添加碳源糖组与C/N为10∶1、11∶1组NO3-的积累量存在显著性差异(P<0.05),C/N为10∶1和15∶1组与C/N为12∶1、13∶1和14∶1组NO3-的积累量存在显著性差异(P<0.05)。6个处理组ORP在实验第一天都迅速下降到负值,但6组间ORP变化均无显著性差异(P>0.05)。将NO3-积累量有显著差异性的3个处理组(不添加碳源组, C/N=10、12组)进行高通量测序,发现3个处理组第一优势菌门和第一优势菌纲均为放线菌门和放线菌纲。在属水平中,芽孢杆菌属的丰度随着C/N的增加逐渐上升。综上所述,不添加碳源组的硝化作用强度最强,其余各处理组硝化作用强度随着C/N的升高逐渐降低。

     

    Abstract: In order to explore the effects of different C/N(C is the quality of carbon elements in glucose; N is the total nitrogen content in feed) on bio-flocculation nitrification intensity and microbial community, five different gradients of C/N ratio were set(10:1, 15:1, 20:1, 25:1 and 30:1). The results showed that the accumulation of NO3-in C/N(10:1, 15:1) were significantly higher than that in other groups(P<0.05), and also between C/N(10:1, 15:1)(P<0.05).Oxidation-reduction potential(ORP) of the five groups dropped to a negative value in the first day, but there were no significant differences about the change of ORP among the five groups(P>0.05). Based on saving carbon source, another five different gradients(C/N=10:1, 11:1, 12:1, 13:1, 14:1) were set, and the control group added with no glucose. The results showed that the accumulation of NO3-was gradually decreased with the increase of C/N, and the accumulation of NO3-in the group added with no glucose was significantly higher than that in other groups(P<0.05). There were significant differences about accumulation of NO3-between the group added with no glucose and C/N(10:1, 11:1), and also between C/N(10:1, 11:1) and C/N(12:1, 13:1, 14:1)(P<0.05). ORP dropped rapidly to a negative value in the second batch of experiment, but there were no significant differences in the change of ORP among the six groups(P>0.05). Then, high-throughput sequencing was carried out in three groups(Control group, C/N(10:1, 12:1) which had significant differences about the accumulation of NO3-, and the results showed that the first dominant phylum and class in the three groups were actinomycetes phylum and actinomycetes class,respectively. And the abundance of Bacillus generic gradually increased with the increase with C/N in the three groups. In conclusion, the nitrification intensity in the control group added with no glucose was better than that in other groups, and the nitrification intensity gradually decreased with the increase of C/N.

     

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