Liu An-Chi, Chou Chu-Yang, Chen Ling-Ling, Kuo Chih-Horng
Department of Bio-Industrial Mechatronics Engineering/Bioenergy Research Center, National Taiwan University, No. 1, Section 4, Roosevelt Road, Taipei 10617, Taiwan.
Institute of Plant and Microbial Biology, Academia Sinica, 128 Sec. 2, Academia Road, Nankang, Taipei 11529, Taiwan.
J Biotechnol. 2015 Jan 20;194:124-31. doi: 10.1016/j.jbiotec.2014.11.026. Epub 2014 Dec 11.
Anaerobic digestion is a microbiological process of converting organic wastes into digestate and biogas in the absence of oxygen. In practice, disturbance to the system (e.g., organic shock loading) may cause imbalance of the microbial community and lead to digester failure. To examine the bacterial community dynamics after a disturbance, this study simulated an organic shock loading that doubled the chemical oxygen demand (COD) loading using a 4.5L swine wastewater anaerobic completely stirred tank reactor (CSTR). Before the shock (loading rate=0.65gCOD/L/day), biogas production rate was about 1-2L/L/day. After the shock, three periods representing increased biogas production rates were observed during days 1-7 (∼4.0L/L/day), 13 (3.3L/L/day), and 21-23 (∼6.1L/L/day). For culture-independent assessments of the bacterial community composition, the 454 pyrosequencing results indicated that the community contained >2500 operational taxonomic units (OTUs) and was dominated by three phyla: Bacteroidetes, Firmicutes, and Proteobacteria. The shock induced dynamic changes in the community composition, which was re-stabilized after approximately threefold hydraulic retention time (HRT). Intriguingly, upon restabilization, the community composition became similar to that observed before the shock, rather than reaching a new equilibrium.
厌氧消化是一个在无氧条件下将有机废物转化为消化物和沼气的微生物过程。在实际操作中，系统受到干扰（如有机冲击负荷）可能会导致微生物群落失衡并致使消化池失效。为了研究干扰后细菌群落的动态变化，本研究使用一个4.5升的猪废水厌氧全混式反应器（CSTR）模拟了化学需氧量（COD）负荷翻倍的有机冲击负荷。在冲击之前（负荷率 = 0.65克COD/升/天），沼气产生速率约为1 - 2升/升/天。冲击之后，在第1 - 7天（约4.0升/升/天）、第13天（3.3升/升/天）以及第21 - 23天（约6.1升/升/天）观察到了代表沼气产生速率增加的三个阶段。对于细菌群落组成的非培养评估，454焦磷酸测序结果表明该群落包含超过2500个可操作分类单元（OTU），并且以三个门为主：拟杆菌门、厚壁菌门和变形菌门。冲击引起了群落组成的动态变化，在大约三倍水力停留时间（HRT）后重新稳定。有趣的是，重新稳定后，群落组成变得与冲击前观察到的相似，而不是达到一个新的平衡。
