초록
Long fermentation time and high residual sugar concentration represent significant challenges for the ethanol production from inulin-containing feedstock by Kluyveromyces marxianus, which possesses the advantages of high temperature resistance, rapid growth and high level of native inulinase secretion. To solve the problems, an applicable strategy in ethanol production from inulin was developed. Batch fermentations were conducted by oxidation-reduction potential (ORP) control. When the ORP was controlled at -130mV, the highest ethanol concentration and productivity, 97.7g/L and 2.04g/L/h, were achieved, with the residual sugar concentration of 3g/L. The high cell viability ensured an effective conversion of total sugar to ethanol, leading to a low sugar concentration at the terminal. Metabolic flux analysis (MFA) demonstrated that significant differences in EMP, PPP and some nodes after pyruvate under different ORPs. With the increase of ORP from -150 to -100mV, total sugar uptake rate increased from 195.11 to 223.13Cmmol/L/h. Controlling ORP at -130mV was the most suitable strategy for the industrialization of ethanol production from inulin reported so far.