碳氮比对硝化过程微生物代谢及功能基因的影响

Effect of C/N Ratio on Microbial Metabolism and Related Functional Genes in Biological Nitrification Process

生物脱氮效率受进水碳氮比(C/N)的影响较大。为此,采用人工模拟配水,基于16S rRNA高通量测序技术,探究了SBR生物脱氮过程中,4种C/N(0、5、10和15)条件对微生物代谢功能及相关功能基因的影响。结果表明,C/N对微生物菌群的代谢功能有不同程度的影响。能量代谢、碳水化合物代谢和氨基酸代谢是影响微生物代谢活性的主导功能。碳水化合物代谢和能量代谢在R0中的相对丰度最高,而丁酸代谢、丙酸代谢和氮代谢在R0中的相对丰度最低。此外,C/N可显著影响氮代谢过程相关功能基因的数量,当C/N从0逐渐升高至15时,硝化过程相关酶的相对丰度表现为先增大后减小的趋势;反硝化过程相关酶的相对丰度逐渐增大,固氮过程相关酶的相对丰度却逐渐减小。

Ratio of carbon-nitrogen(C/N)is one of the key factors affecting the efficiency of biological denitrification.Experiments were carried out in four lab-scale sequencing batch reactors fed with synthetic wastewater with C/N ratio of 0,5,10 and 15 respectively.The effect of C/N ratio on microbial metabolism and related functional genes in SBR biological denitrification process was explored by means of 16S rRNA high-throughput sequencing technology.The results showed that C/N ratio had different effects on the metabolic function of microbial community.Energy metabolism,carbohydrate metabolism and amino acid metabolism were the main functions that affected the metabolic activity of microorganisms.The relative abundances of carbohydrate metabolism and energy metabolism were the highest in R0,while the relative abundances of butanoate metabolism,propanoate metabolism and nitrogen metabolism were the lowest.In addition,C/N ratio could significantly affect the number of relative functional genes in nitrogen metabolism process.When C/N ratio increased from 0 to 15,the relative abundance of related enzymes in nitrification increased at the beginning,and then decreased;the relative abundance of related enzymes in denitrification gradually increased,but the relative abundance of related enzymes in nitrogen fixation tended to decrease.