以pH为扰动因子探究电化学厌氧消化产甲烷代谢通量与微生物的关系

Exploring the relationship between methane flux and microorganisms in electrochemical anaerobic digestion system by using pH as a disturbance factor

【背景】电化学厌氧消化(electrochemical anaerobic digestion,EAD)系统的代谢途径由具备不同功能的微生物所主导,其代谢通量与功能微生物丰度、活性及群落结构相关。【目的】探究EAD产甲烷代谢通量与微生物的关系。【方法】采用代谢通量分析(metabolic flux analysis,MFA)方法,以pH为扰动因子得到微生物群落与产甲烷通量的响应关系。【结果】pH 7.5扰动时产甲烷通量最大为0.3984±0.0293,较对照组(pH 6.9)的0.2974±0.0127和扰动组(pH 6.3)的0.1365±0.0120分别提高了25%和65%。另外,平均有33.8%±3.1%的氢气(通量)用于还原二氧化碳产甲烷和乙酸,平均有21.0%±2.6%的乙酸(通量)转化为甲烷。此外,产甲烷通量与Mariniphaga、Methanosaeta和Desulfomicrobium的丰度呈正相关,与Sedimentibacter的丰度呈负相关且影响显著。【结论】在EAD产甲烷体系中产甲烷菌和产酸菌共存时,pH值略大于7.0的环境有利于甲烷的生成,改变EAD体系的pH可有效调控代谢产物的通量,其通量大小受微生物丰度的影响较大。

[Background]The metabolic pathway of electrochemical anaerobic digestion(EAD)system is dominated by microorganisms with different functions,and the metabolic flux is related to the abundance,activity,and community structure of functional microorganisms.[Objective]To explore the relationship between methane flux and microorganisms in the EAD system.[Methods]We conducted the metabolic flux analysis by using pH as a disturbance factor.[Results]At pH 7.5,the maximum methane flux was 0.3984±0.0293,which was 25%and 65%higher than that 0.2974±0.0127 in the control group(pH 6.9)and that 0.1365±0.0120 in the disturbance group(pH 6.3),respectively.In addition,an average of 33.8%±3.1%of hydrogen(flux)was used to reduce carbon dioxide to produce methane and acetic acid,and an average of 21.0%±2.6%of acetic acid(flux)was converted into methane.The methane flux was positively correlated with the abundance of Mariniphaga,Methanosaeta,and Desulfomicrobium,while negatively correlated with that of Sedimentibacter.[Conclusion]In the EAD system with the coexistence of methane and acid-producing bacteria,a pH value slightly greater than 7.0 is conducive to the production of methane,and changing the pH value of the EAD system can regulate the metabolite flux by altering microbial abundance.