College of Agronomy and Biotechnology, China Agricultural University, Beijing 100193, China.
College of Agronomy and Biotechnology, China Agricultural University, Beijing 100193, China.
Bioresour Technol. 2017 Aug;238:542-551. doi: 10.1016/j.biortech.2017.04.080. Epub 2017 Apr 23.
The ready formation of scum in vertical reactors has been a bottleneck in the digestion of lignocellulosic materials for biogas production. This study describes a single vertical reactor that integrates the acidogenic and methanogenic phases of this process. The effects of two types of maize stover feedstock (fresh and silage) and two mixing intensities (20 and 70rpm) on methane yield were orthogonally determined. Fresh maize stover yielded approximately 14% more methane than silage maize stover. Mixing at 20rpm contributed to methane yield, while mixing at 70rpm blurred the phase boundary, resulting in accumulation of volatile fatty acids and loss of methanogens. The upper and lower phases clearly constituted a two-phase fermentation system. Clostridiales occupied the acidogenic phase, while the predominant bacteria in the methanogenic phase were Bacteroidetes, Chloroflexi, and Synergistetes. The absolute predominance of Methanosaetaceae clearly demonstrated that aceticlastic methanogenesis was the main route of methane production.
垂直式反应器中易于形成浮渣一直是木质纤维素原料沼气消化的瓶颈。本研究描述了一种集成了产酸相和产甲烷相的单一垂直式反应器。正交确定了两种类型的玉米秸秆原料（新鲜和青贮）和两种混合强度（20rpm 和 70rpm）对甲烷产量的影响。新鲜的玉米秸秆比青贮玉米秸秆产生的甲烷多约 14%。20rpm 的混合有助于甲烷产量，而 70rpm 的混合则模糊了相界面，导致挥发性脂肪酸的积累和产甲烷菌的损失。上下相明显构成了两相发酵系统。产酸相中主要是梭菌属，而产甲烷相中主要的细菌是拟杆菌门、绿弯菌门和互营菌门。产甲烷菌科的绝对优势清楚地表明，乙酸营养型产甲烷是甲烷产生的主要途径。
