Rumen microorganisms have the ability to efficiently hydrolyze and acidify lignocellulosic biomass. The effectiveness of long-term rumen microorganism fermentation of lignocellulose in vitro for producing volatile fatty acids (VFAs) is unclear. The feasibility of long-term rumen microorganism fermentation of lignocelluose was evaluated in this study, and a stable VFA production was successfully realized for 120 d. Results showed that VFA concentration reached to 5.32–8.48 g/L during long-term fermentation. Hydrolysis efficiency of hemicellulose and cellulose reached 36.5%-52.2% and 29.4%-38.4%, respectively. A stable bacterial community was mainly composed of Prevotella, Rikenellaceae_RC9_gut_group, Ruminococcus, and Succiniclasticum. VFA accumulation led to a pH decrease, which caused the change of bacterial community structure. Functional prediction showed that the functional genes related to hydrolysis and acidogenesis of corn stover were highly expressed during long-term fermentation. The successful long-term rumen fermentation to produce VFAs is of great significance for the practical application of rumen microorganisms.

瘤胃微生物具有有效水解和酸化木质纤维素生物质的能力。长期瘤胃微生物体外发酵木质纤维素生产挥发性脂肪酸（VFAs）的有效性尚不清楚。本研究评价了长期瘤胃微生物发酵木质纤维素的可行性，并成功实现了120 d的稳定VFA生产。结果表明，在长期发酵过程中，VFA浓度达到5.32-8.48 g/L。半纤维素和纤维素的水解效率分别达到36.5%-52.2%和29.4%-38.4%。一个稳定的细菌群落主要由普氏菌、Rikenellaceae_RC9_gut_group、Ruminococcus和Succiniclasticum组成。. VFA积累导致pH降低，从而引起细菌群落结构的变化。功能预测表明，玉米秸秆水解和酸化相关的功能基因在长期发酵过程中高表达。成功的长期瘤胃发酵生产VFAs对瘤胃微生物的实际应用具有重要意义。