通气量和菊粉浓度对克鲁维酵母乙醇发酵的影响

Effect of aeration and inulin concentration on ethanol production by Kluyveromyces marxinaus YX01

摘要:

马克斯克鲁维酵母能够利用集成生物加工技术发酵菊芋生产乙醇，具有非粮燃料乙醇生产潜力。文中研究了该技术中的两个关键因素 (通气量和底物浓度) 对于K. marxinaus YX01乙醇发酵过程和菊粉酶活性的影响。研究结果表明，底物浓度对乙醇得率影响不大，底物浓度为250 g/L时，发酵终点乙醇浓度为 84.74 g/L, 但乙醇得率由低浓度50 g/L的86.4％ (理论值)，降为84.7％。通气能够加速K. marxinaus YX01的乙醇发酵过程，但降低了乙醇得率，当底物浓度为250 g/L时，乙醇得率由不通气的84.7％降为1.0 vvm时的73.3％。随底物浓度的升高及通气量的降低，K. marxinaus YX01分泌的菊粉酶活力表现出降低的趋势。在不通气及底物浓度为250 g/L时，菊粉酶的活性为6.59 U/mL，而底物浓度50 g/L，通气量1.0 vvm时的酶活力为21.54 U/mL。乙醇发酵过程中的副产物甘油随通气量的降低及底物浓度的升高而增大，而乙酸的浓度随通气量的增大及底物浓度的升高而升高。

Abstract:

Consolidated bioprocessing technology can be used for Kluyveromyces marxianus YX01 to produce ethanol from Jerusalem artichoke, which is one of the potential processes to produce biofuel from non-cereal crops. In this study, we combined the aeration rate with the substrate concentration to conduct cross-over experiments for K. marxinaus YX01, and studied ethanol fermentation and the influence of inulin enzyme activity. The substrate concentration had a little repressive effect on ethanol productivity. When substrate concentration reached 250 g/L under anaerobic conditions, ethanol concentration was 84.8 g/L, and ethanol yield was reduced from 86.4% (50 g/L substrate concentration) to 84.7% of the theoretical value. Aeration rate could accelerate K. marxinaus YX01 ethanol fermentation, but reduced ethanol yield. When substrate concentration reached 250 g/L under aeration at 1.0 vvm, ethanol yield was reduced from 84.7% under anaerobic conditions to 73.3% of the theoretical value. With increased concentration of the carbon source and reduced aeration rate, the inulinase of K. marxinaus YX01 reduced and the concentration of glycerol increased, however, the acetic acid increased with the increased concentration of the carbon source and aeration rate. When substrate concentration reached 250 g/L under anaerobic conditions, inulinase activity was only 6.59 U/mL; when substrate concentration reached 50 g/L under aeration at 1.0 vvm, inulinase activity was 21.54 U/mL.