温度对硝化杆菌(Nitrobacter)活性动力学影响

Effect of Temperature on the Activity Kinetics of Nitrobacter

为探究温度对亚硝酸盐氧化细菌中硝化杆菌属(Nitrobacter)活性动力学影响,本试验采用序批式活性污泥(SBR)反应器,在通过改变系统进水亚硝态氮(NO_2^--N)浓度达到富集Nitrobacter基础上,以富含Nitrobacter污泥为对象(宏基因组物种注释和丰度分析显示Nitrobacter占细菌总数40. 3%),考察不同NO_2^--N浓度梯度下亚硝酸盐氧化过程比亚硝态氮氧化速率(SNi OR)变化规律,基于Monod模型考察系统温度对Nitrobacter活性动力学影响,并进行统计学分析.结果表明,30℃条件下SNi OR达到最大(以N/VSS计),为1. 31 g·(g·d)^(-1).统计学分析结果显示,Monod方程可较好地反映不同温度条件下基质底物浓度对Nitrobacter活性影响.基于菲尔普斯方程计算不同温度区间内温度系数(θ)可知,当系统温度低于25℃或高于30℃时,反应速率随温度变化越敏感.

A sequencing batch reactor(SBR)was operated in this study to investigate the effect of temperature on the kinetics of Nitrobacter activity among nitrite oxidizing bacteria.At the beginning of the experiment,the NO2--N concentration in the influent was changed to enrich Nitrobacter.Then,the sludge with enriched Nitrobacter was employed to determine the variation of the specific nitrite oxidation rate(SNi OR)during the nitrite oxidation process in batch tests.Metagenomics species annotation and abundance analysis showed that Nitrobacter accounted for 40.3%of the total bacterial population.The variation of SNi OR in the nitrite oxidation process was investigated under different NO2--N concentrations.The effect of temperature on the kinetics of Nitrobacter was investigated using the Monod model.Furthermore,the kinetics model of the effect of temperature on Nitrobacter activity was fitted for statistical analysis.The results showed that SNi OR reached its maximum at 30℃,which was 1.31 g·(g·d)-1.Statistical analysis showed that the Monod equation could describe the effect of substrate concentration on Nitrobacter activity under different temperature conditions.Calculating the temperature coefficient(θ)in different temperature intervals based on the Phelps equation,showed that when the system temperature is lower than 25℃or higher than 30℃,the reaction rate is more sensitive to temperature changes.