The effects of pore sizes on the in-situ utilization of synthesis gas (syngas, H₂ and CO) mixed culture fermentation (MCF) in the hollow-fiber membrane biofilm reactor (HfMBR) are not clear. Thus, the ultrafiltration (R1) and microfiltration (R2) HfMBRs were constructed. Syngas was totally consumed within the formed biofilm in R1; contrarily, it accumulated notably in R2. In the batch mode of R1 and R2, volatile fatty acids (VFAs) of acetate, butyrate and caproate were the main metabolites, but the production rate of total VFA in R1 (61.9 mmol-C/(L·d)) was higher than that of R2 (27.6 mmol-C/(L·d)). In the continuous mode, the R1 performance was much better than that of R2, and the biofilm in R2 was even washed out. Furthermore, Clostridium (30.0%) was the main genus in the enriched biofilm of R1, which converted syngas to VFAs. Thus, the ultrafiltration membrane shall be the suitable candidate for syngas MCF.

在中空纤维膜生物膜反应器（HfMBR）中，孔径对合成气（syngas，H ₂和CO）混合培养发酵（MCF）原位利用的影响尚不清楚。因此，构建了超滤（R1）和微滤（R2）HfMBR。R1中形成的生物膜完全消耗了合成气；相反，它明显地在R2中积累。在R1和R2的分批模式下，乙酸，丁酸和己酸的挥发性脂肪酸（VFA）是主要的代谢产物，但R1中总VFA的生产率（61.9 mmol-C /（L·d））高于R 2（27.6mmol-C /（L·d））。在连续模式下，R1的性能比R2更好，R2中的生物膜甚至被冲洗掉。此外，梭菌（30.0％）是R1富集的生物膜的主要属，该生物膜将合成气转化为VFA。因此，超滤膜将是合成气MCF的合适候选者。