摘要
Bioethanol fermentation experiments were conducted in a shaking flask and a 10 L fluidized bed bioreactor with stalk juice of SNTZ No.2 sweet sorghum variety when immobilized yeast was applied. The objectives of the study were to investigate the effects of inorganic salts on ethanol fermentation of sweet sorghum juice and to observe performance of fluidized bed bioreactor. L9（34） orthogonal experimental method was used in shaking flask experiments. Results showed that the influence sequence to improve ethanol yield was （NH4）2SO4, MgSO4, K2HPO4 for SNTZ No.2 sweet sorghum variety. The optimum ratio of K2HPO4, （NH4）2SO4 and MgSO4 were 0.125%, 0.2% and （0.05）%, respectively. At the optimum ratio, the fermentation time was short and the ethanol content was high in fluidized bed reactor fermentation, which were 5 h and 7.2%（v/v）, respectively. The calculated ethanol yield was 93%. The fermentation time was shortened by 1～3 h and ethanol yield at the end of fermentation was increased by 2%8% than without inorganic salts; In addition, the results showed that the fermentation time was about six times shorter in fluidized bed bioreactor with immobilized yeast than that of conventional fermentation technology. Therefore, it can be concluded that the fluidized bed bioreactor with immobilized yeast should be applied for ethanol production from sweet sorghum. And ratio of inorganic salts should be considered for refining bio-ethanol from juice of sweet sorghum stalk in order to shorten fermentation time and increase ethanol yield.
Bioethanol fermentation experiments were conducted in a shaking flask and a 10 L fluidized bed bioreactor with stalk juice of SNTZ No.2 sweet sorghum variety when immobilized yeast was applied. The objectives of the study were to investigate the effects of inorganic salts on ethanol fermentation of sweet sorghum juice and to observe performance of fluidized bed bioreactor. L_9(3~4) orthogonal experimental method was used in shaking flask experiments. Results showed that the influence sequence to improve ethanol yield was (NH_4)_2SO_4, MgSO_4, K_2HPO_4 for SNTZ No.2 sweet sorghum variety. The optimum ratio of K_2HPO_4, (NH_4)_2SO_4 and MgSO_4 were 0.125%, 0.2% and (0.05)%, respectively. At the optimum ratio, the fermentation time was short and the ethanol content was high in fluidized bed reactor fermentation, which were 5 h and 7.2%(v/v), respectively. The calculated ethanol yield was 93%. The fermentation time was shortened by 1～3 h and ethanol yield at the end of fermentation was increased by 2%~8% than without inorganic salts; In addition, the results showed that the fermentation time was about six times shorter in fluidized bed bioreactor with immobilized yeast than that of conventional fermentation technology. Therefore, it can be concluded that the fluidized bed bioreactor with immobilized yeast should be applied for ethanol production from sweet sorghum. And ratio of inorganic salts should be considered for refining bio-ethanol from juice of sweet sorghum stalk in order to shorten fermentation time and increase ethanol yield.
基金
Foundation item: Item supported by Liaoning province pro-ject(2003224003)
EC project(ICA4-2002-10023).
