自产气气提与纤维床反应器耦合发酵生产丁醇

采用发酵产物中的二氧化碳（CO₂）和氢气（H₂）作为循环气提气源，对丙酮丁醇梭菌（Clostridium acetobutylicum CGMCC 5234）发酵产物进行原位气提，实现丙酮、丁醇和乙醇混合物（ABE）的连续纤维床固定化发酵生产。连续发酵实验进行了12批次共309 h，总溶剂ABE当量浓度为133.3 g·L^-1（其中丁醇 83.5 g·L^-1，丙酮38.4 g·L^-1，乙醇11.4 g·L^-1），葡萄糖消耗率为1.29 g·（L·h） ^-1，总溶剂ABE产率为0.431 g·（L·h） ^-1，转化率为0.333 g·g^-1，其中丁醇产率为0.270 g·（L·h） ^-1，转化率为 0.209 g·g^-1，发酵液中丁醇浓度控制在8～12 g·L^-1，显著优于游离发酵的结果。气提提取之后冷凝的ABE溶液出现分层现象，其中丁醇相丁醇浓度高达603.7 g·L^-1，极大地减缓后续分离提纯的负担。结果表明，自产气循环气提与纤维床固定化耦合连续发酵生产ABE（特别是丁醇）的工艺具有可行性和竞争力。

Butanol fermentation by fibrous bed bioreactor integrated with gas stripping

Acetone-butanol-ethanol (ABE) fermentation with Clostridium acetobutylicum CGMCC 5234 immobilized in fibrous bed bioreator was studied for its potential utilization to produce ABE that can be easily recovered by gas stripping with gas products CO₂ and H₂. The process was conducted in fed-batch fermentation for twelve feeding cycles over 309 h, and 133.3 g·L^-1 ABE(83.5 g·L^-1 butanol, 38.4 g·L^-1 acetone, 11.4 g·L^-1 ethanol) was produced. The overall productivity and yield were 0.431 g·(L·h)^-1 and 0.333 g·g^-1 for ABE and 0.270 g·(L·h)^-1 and 0.209 g·g^-1 for butanol. The concentration of butanol in the fermentation liquid was 8—12 g·L^-1. Phase separation of condensed ABE after gas stripping with up to 603.7 g·L^-1 butanol in the butanol phase would relieve the burden of subsequent separation and purification. The results showed that the fed-batch fermentation with intermittent gas stripping was feasible and competitive.