Ma Tingting, Cheng Lei, Zheng Zhenzhen, Qin Qianshan, Dai Lirong, Zhang Hui
Wei Sheng Wu Xue Bao. 2014 Dec 4;54(12):1453-61.
To evaluate the effects of pH on methane production from acetate and the methanogenic community structures.
Solutions of phosphate (PB), 2-hydroxyethyl (HEPES), NaHCO3/CO2 or piperazine-1,4-bisethanesulfonic acid (PIPES) were added into the methanogenic cultures, separately. The substrate consumption was determined by monitoring cumulative methane production, the methanogenic community structuresin the stationary-phase cultures were analyzed using terminal restriction fragment length polymorphism (T-RFLP) of 16S rRNA gene fragments.
The period of lag phase of methane production in the PB addition culture (ca. 40 d) was much longer than that in other pH buffer cultures (20 - 24 d, P < 0.05). Approximate 88.3% of acetate was converted into methane in the NaHCO3/CO2 addition culture, while the value decreased to 77% - 81% in other pH buffer cultures (P < 0.05). The maximum specific methane production rate was similar between different pH buffer cultures (P > 0.05). The relative abundance of members of unclassified bacteria, Spirochaetaceae and uncultured WWE1 increased to (15.5 ± 9.4)%, (7.3 ± 4.6)% and (17.6 ± 6.3)%, respectively, in the NaHCO3/CO2 addition culture, while synergistaceae decreased to (8.9 ± 8.1)%. In archaeal domain, the acetotrophic methanogen related with Methanosaeta harundinacea became predominant (97 ± 2%) in the PB buffer culture, on the contrary, the concurrence of M. harundinacea, M. concilii and hydrogenotrophic methanogen related with Methanobacteriales were detected in the cultures amended with HEPES, PIPES and NaHCO3/CO2.
PB retarded the methane production in the acetatemethanogenic culture, NaHCO3/CO2 addition improve methane production from acetate, the pH buffers had not obvious effects on the maximum specific methane production rate of the cultures, the microbial community structures obviously changed along with PB and NaHCO3/CO2 addition. The research would help us to design suitable condition for the growth of methanogenic culture.
评估pH对乙酸盐产甲烷及产甲烷菌群结构的影响。
将磷酸盐（PB）、2-羟乙基（HEPES）、NaHCO₃/CO₂或哌嗪-1,4-双乙烷磺酸（PIPES）溶液分别添加到产甲烷培养物中。通过监测累积甲烷产量来测定底物消耗情况，利用16S rRNA基因片段的末端限制性片段长度多态性（T-RFLP）分析稳定期培养物中的产甲烷菌群结构。
添加PB的培养物中产甲烷延迟期（约40天）远长于其他pH缓冲液培养物（20 - 24天，P < 0.05）。添加NaHCO₃/CO₂的培养物中约88.3%的乙酸盐转化为甲烷，而在其他pH缓冲液培养物中该值降至77% - 81%（P < 0.05）。不同pH缓冲液培养物的最大比产甲烷速率相似（P > 0.05）。在添加NaHCO₃/CO₂的培养物中，未分类细菌、螺旋体科和未培养的WWE1成员的相对丰度分别增至（15.5 ± 9.4）%、（7.3 ± 4.6）%和（17.6 ± 6.3）%，而协同菌科降至（8.9 ± 8.1）%。在古菌域，与哈尔氏甲烷八叠球菌相关的乙酸营养型产甲烷菌在PB缓冲液培养物中占主导（97 ± 2%），相反，在添加HEPES、PIPES和NaHCO₃/CO₂的培养物中检测到哈尔氏甲烷八叠球菌、和解甲烷菌以及与甲烷杆菌目相关的氢营养型产甲烷菌同时存在。
PB延缓了乙酸盐产甲烷培养物中的甲烷生成，添加NaHCO₃/CO₂提高了乙酸盐的产甲烷量，pH缓冲液对培养物的最大比产甲烷速率无明显影响，微生物群落结构随PB和NaHCO₃/CO₂的添加而明显改变。该研究有助于我们设计适合产甲烷培养物生长的条件。
