牛粪堆肥过程中nosZ型反硝化细菌动态变化

Dynamic community structure of nosZ-type denitrifying bacteria during cow manure composting

采用高通量测序技术,研究牛粪堆肥过程中不同时期与不同深度的nosZ型反硝化细菌群落组成的动态变化与多样性,并通过冗余分析(Redundancy analysis,RDA)和Spearman相关性分析,揭示了堆肥过程中nosZ型反硝化细菌与理化指标之间的相关关系。结果表明,堆肥不同时期nosZ型反硝化细菌群落结构差异显著,反硝化细菌群落多样性和丰富度均呈先降低后升高的趋势,在堆肥降温期不同深度的反硝化细菌群落结构和多样性指数差异显著。此外,理化因素显著影响堆肥反硝化菌群的群落结构与多样性,螯台球菌属(Chelatococcus)与温度呈极显著正相关(P<0.01),Polymorphum与硝态氮呈极显著正相关(P<0.01),生根瘤菌属(Mesorhizobium)与含水率和C/N呈极显著负相关(P<0.01)。反硝化细菌的多样性与温度、pH、氨态氮呈极显著负相关(P<0.01),与硝态氮呈极显著正相关(P<0.01)。反硝化细菌的丰富度与温度呈极显著负相关(P<0.01)。综上所述,堆肥时间和深度均为影响nosZ型反硝化细菌群落结构的重要因素,且该菌群群落结构变化受理化因子的显著影响。

This study examined the dynamic nature and diversity of the community structure of the nosZ-type denitrifying bacteria with varying periods and layers during cow manure and rice straw composting.This was done via high throughput sequencing.The relationship between the denitrifying bacteria and physicochemical parameters was investigated using redundancy analysis(RDA)and Spearman correlation analysis.The results indicated that the community structure of the nosZ-type denitrifying bacteria varied significantly through the composting stages.Further,both the diversity and richness of the denitrifying bacteria displayed a declining tendency at the beginning and an increasing trend in late phase of composting.The denitrifying bacterial community structure and diversity index were greatly affected by composting depth in the late thermophilic stage.In addition,physicochemical parameters significantly affected the community structure.Significantly positive correlations were observed between Chelatococcu and temperature(P<0.01),andPolymorphum and nitrate nitrogen(P<0.01).Significantly negative correlations were seen between Mesorhizobium and moisture content and C/N(P<0.01).The diversity of the denitrifying bacterial communities was significantly negatively correlated with temperature,pH,and ammonium nitrogen(P<0.01)and significantly positively correlated with nitrate nitrogen(P<0.01).The richness of the denitrifying bacteria was significantly negatively correlated with temperature(P<0.01).In conclusion,our results indicate that time and depth are both factors influencing the nosZ-type denitrifying bacterial community structure,and the community structure is significantly affected by physicochemical parameters.This study pro?vides an insight into the theory of the role of the nitrogen cycle in composting and thus promotes the improvement of composting technology.