Abstract:

In order to develop the new technology of ethanol production from synthesis gas fermentation,the growth characteristics and carbon monoxide (CO) fermentation performance of C.autoethanogenum were investigated.The effects of different carbon sources on the growth of C.autoethanogenum were analyzed and the results show that xy- lose is the optimal substrate.After the growth medium being modified,the cell density of C.autoethanogenum in- creased by more than 2 times,and the metabolic products were mostly acetic acid with a small amount of ethanol.Moreover,the CO fermentation performance of C.autoethanogenum was studied in 1L gas sampling bags.After twice CO fermentation with C.autoethanogenum in the fermentation medium containing 1.0g/L yeast extract,an ethanol concentration of 3.464g/L was achieved,and the yield of ethanol from CO reached 51.7%.The investigation re- sults also indicate that the hydrolysate of bagasse treated with hot liquid water at 180℃ in a 4MPa N 2 atmosphere for 20min can be utilized to culture C.autoethanogenum,and the corresponding ethanol concentration and ethanol yield from CO can reach 3.13g/L and 46.9%,respectively after only once CO fermentation,which are similar to the results of the twice CO fermentation but with much less culture time.

Key words: synthesis gas, ethanol, carbon monoxide, gas fermentation