초록
<P><B>Abstract</B></P> <P>The application of biodiesel derived crude glycerol for ethanol production using <I>Enterobacter aerogenes</I> TISTR 1468 involved multiple interactions among substrate (glycerol), impurities (methanol) and product (ethanol and acetic acid). A mathematical model based on Monod and Luedeking-Piret models were established to simulate the cell performance in the presence of inhibitors. The Monod model was modified by adding the inhibition factors in terms of critical concentration (C*<SUB>Ac</SUB>< C*<SUB>EtOH</SUB>< C*<SUB>MeOH</SUB>< C*<SUB>Gly</SUB>) and its inhibition degree (ni) (n<SUB>Gly</SUB>>n<SUB>MeOH</SUB>>n<SUB>Ac</SUB>>n<SUB>EtOH</SUB> with the values of 119.06, 13.33, 1 and 0.0383, respectively). The Luedeking-Piret model confirmed that ethanol and acetic acid were predominantly growth-associated products. Glycerol up to 24.31 g/L and 31.32 g/L were optimum for cell growth and ethanol productivity, respectively. The cell performance was affected by methanol even at its lowest concentration tested (7.92 g/L). The applicability of the new two-phase growth model during the growth phase and stationary phase in the crude glycerol medium was validated and proved accurate (r<SUP>2</SUP>> 0.98).</P> <P><B>Highlights</B></P> <P> <UL> <LI> Two-Phase model was developed to simulate the performance of <I>E. aerogenes</I>. </LI> <LI> Degree of inhibition (n) described the change on cell’s performance. </LI> <LI> Methanol concentration in crude glycerol had an influence on critical glycerol concentration. </LI> <LI> Glycerol concentration of 22 g/L containing 3.5 g/L methanol gave the highest ethanol production. </LI> </UL> </P>