Production of acetone and butanol from starch by continuous bioprocess

Abstract

Conversions of saccharified and non-saccharified starch to acetone, butanol and ethanol (ABE) with a continuous culture of Clostridium acetobutylicum were investigated and compared with regard to products and productivity. It was found, that compared with the microbial process using saccharified starch, the process using non-saccharified starch produced ABE in considerably lower concentrations at dilution rates of >0.15 h −1. Two-stage continuous bioprocess using non-saccharified starch resulted in no appreciable increase in acetone and butanol concentrations. For the reasons given above, preliminary saccharification processing is recommended for the production of ABE from starch using a continuous bioprocess. A two-stage process was developed for continuous production of ABE from saccharified starch. By this process, 15 g l −1 ABE are produced at the rate of 3.3 g l −1 h −1.