초록
Two-stage gas stripping for butanol recovery from acetone-butanol-ethanol (ABE) fermentation with Clostridium acetobutylicum JB200 in a fibrous bed bioreactor was studied. Compared to fermentation without in situ gas stripping, more ABE (10.0g/L acetone, 19.2g/L butanol, 1.7g/L ethanol vs. 7.9g/L acetone, 16.2g/L butanol, 1.4g/L ethanol) were produced, with a higher butanol yield (0.25g/g vs. 0.20g/g) and productivity (0.40g/L.h vs. 0.30g/L.h) due to reduced butanol inhibition. The first-stage gas stripping produced a condensate containing 175.6g/L butanol (227.0g/L ABE), which after phase separation formed an organic phase containing 612.3g/L butanol (660.7g/L ABE) and an aqueous phase containing 101.3g/L butanol (153.2g/L ABE). After second-stage gas stripping, a highly concentrated product containing 420.3g/L butanol (532.3g/L ABE) was obtained. The process is thus effective in producing high-titer butanol that can be purified with much less energy.