qPCR揭示丙酸降解菌群随OLR提高的演替规律

qPCR reveals the succession of syntrophic propionate-degrading consortia with OLR increase

为探讨有机负荷率(OLR)对升流式厌氧污泥床(UASB)反应器运行效能的影响及互营丙酸降解菌群的响应,以稀释的制糖废水为底物,考察了OLR升高对UASB处理效能的影响,并采用实时荧光定量PCR技术(qPCR)分析了互营丙酸降解菌群随OLR提高的演替规律.结果表明,在OLR为6.0～54.0kg COD/(m^3·d)的范围内,UASB处理制糖废水取得了良好的效果,其COD去除率为92.0%以上.qPCR检测结果表明,至少有3种已鉴定的丙酸氧化菌(Pelotomaculum schinkii,P.propionicum和Syntrophobacter sulfatireducens)存在于UASB反应器中.其中,S.sulfatireducens是主要的丙酸氧化菌,其数量为126～1.2×10~3 16S rRNA基因拷贝数/ng DNA,约占检测到丙酸氧化菌总数的47.9%～58.6%.OLR从6.0提高至54.0kg COD/(m^3·d)导致所有丙酸氧化菌数量显著减少.Methanospirillum hungatei和Methanosaeta concilii是该UASB系统中的主要氢营养型产甲烷菌和乙酸营养型产甲烷菌.与丙酸氧化菌的变化趋势相反,这两种产甲烷菌的数量均随OLR的提高而显著增加,并在OLR54.0kg COD/(m^3·d)条件下达到最大值.

To reveal the effects of organic loading rate（OLR） on the performance of upflow anaerobic sludge bed（UASB） reactor and syntrophic propionate-degrading consortia, this study investigated the effects of OLR increase on the treatment efficiency of UASB containing sugar refinery wastewater as substrate. The succession of syntrophic propionate-degrading consortia as OLR increasing was analyzed by quantitative real-time fluorescence polymerase chain reaction（qPCR）. The results showed that the COD removal reached above 92.0% in UASB at OLR of 6.0～54.0 kg COD/（m^3·d） conditions. qPCR explored that at least three identified species of propionate-oxidizing bacteria（Pelotomaculum schinkii, P. propionicum, and Syntrophobacter sulfatireducens） existed in the UASB system. S. sulfatireducens was dominated in UASB and its quantity was 126～1.2×10^3 16 S rDNA copies per ng DNA, accounting for 47.9%～58.6% of the total detectable propionate-oxidizing bacteria. OLR increase from 6.0 to 54.0 kg COD/（m^3·d） resulted in all detected propionate-oxidizing bacteria significantly decreased. In addition, Methanospirillum hungatei and Methanosaeta concilii were the dominant hydrogenotrophic methanogens and acetotrophic methanogens. The number of methanogens was significantly increased with OLR increase and achieved a maximum at OLR of 54.0 kg COD/（m^3·d） condition.