초록
<P><B>Abstract</B></P> <P>In this study, utilization of waste cake for bioethanol production via a two-step of enzymatic hydrolysis and ethanol fermentation was developed. At the first step, namely waste cake hydrolysis, effects of α-amylase volumes (C1: 0.1 mL/L, C2: 0.4 mL/L, C3, 0.8 mL/L) on the performance of hydrolysis were investigated. Both chemical oxygen demand (COD) and reducing sugar (RS) could reach the highest values after 80 min for all the conditions. The maximum COD of 86.3 g/L, RS of 44 g/L and waste reduction of 85.2% were achieved at C3. At the second step, namely ethanol fermentation, the produced waste cake hydrolysate was used as the sole feedstock for fermentative ethanol production, and the highest ethanol production of 46.6 g/L and ethanol yield of 1.13 g/g RS were obtained (C3), respectively. This corresponds to an overall ethanol yield of 1.12 g ethanol/g initial dry cake which is the highest ethanol yield compared to using other food wastes reported to date. These values are higher than using the glucose as feedstock since the waste cake hydrolysate could provide the carbon and nitrogen sources for ethanol fermentation.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Feasibility of using waste cake for bioethanol production was investigated. </LI> <LI> Reducing sugar could be released by α-amylase completely within 80 min. </LI> <LI> The waste cake reduction by hydrolysis could reach 84%–85.2%. </LI> <LI> Inhibitory effect for ethanol production was observed at RS concentration of 44 g/L. </LI> <LI> Ethanol yield of 1.12 g ethanol/g initial dry cake was achieved. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>Schematic diagram of utilization of waste cake for fermentative ethanol production.</P> <P>[DISPLAY OMISSION]</P>