|
KMID : 0545120160260081409
|
|
Journal of Microbiology and Biotechnology
2016 Volume.26 No. 8 p.1409 ~ p.1419
|
|
|
Response of Syntrophic Propionate Degradation to pH Decrease and Microbial Community Shifts in an UASB Reactor
|
|
Zhang Li Guo
Ban Qiao Ying
Li Jian Zheng
Jha Ajay Kumar
|
|
|
Abstract
|
|
|
|
The effect of pH on propionate degradation in an upflow anaerobic sludge blanket (UASB) reactor containing propionate as a sole carbon source was studied. Under influent propionate of 2,000 mg/l and 35ºC, propionate removal at pH 7.5-6.8 was above 93.6%. Propionate conversion was significantly inhibited with stepwise pH decrease from pH 6.8 to 6.5, 6.0, 5.5, 5.0, 4.5, and then to 4.0. After long-term operation, the propionate removal at pH 6.5-4.5 maintained an efficiency of 88.5%-70.1%, whereas propionate was hardly decomposed at pH 4.0. Microbial composition analysis showed that propionate-oxidizing bacteria from the genera Pelotomaculum and Smithella likely existed in this system. They were significantly reduced at pH ≤5.5. The methanogens in this UASB reactor belonged to four genera: Methanobacterium, Methanospirillum, Methanofollis, and Methanosaeta. Most detectable hydrogenotrophic methanogens were able to grow at low pH conditions (pH 6.0-4.0), but the acetotrophic methanogens were reduced as pH decreased. These results indicated that propionate-oxidizing bacteria and acetotrophic methanogens were more sensitive to low pH (5.5-4.0) than hydrogenotrophic methanogens.
|
|
|
KEYWORD
|
|
|
Upflow anaerobic sludge blanket reactor, pH decrease, Propionate degradation, Microbial community structure, PCR-DGGE
|
|
|
FullTexts / Linksout information
|
|
|
|
|
|
Listed journal information
|
|
  
|
|