초록
<P><B>Abstract</B></P> <P>Sugarcane bagasse (SB), a by-product from the sugar industry, is considered a promising feedstock for ethanol production, owing to its high cellulose content and its ready availability. In this study, chemically pretreated SB was mixed with dry spent yeast (DSY) at a mass ratio of 60:40 before being fermented under solid-state fermentation (SSF) by <I>Aspergillus niger</I> TK1. The fermented solids at a concentration of 24 g/L (on a dry basis) was subsequently hydrolyzed to produce a hydrolysate, which was concentrated to contain 29.7 ± 0.6 g/L of reducing sugar and 585.1 ± 6.5 mg/L of free amino nitrogen. The concentrated hydrolysate was fermented by <I>Saccharomyces cerevisiae</I> TISTR 5339, yielding 8.98 ± 0.2 g/L of ethanol. An ethanol yield on reducing sugar was 0.46 g/g, which was 90.33% of the theoretical yield. Based on the results, a bioconversion process consisting of SSF followed by hydrolysis of fermented solids and submerged ethanol fermentation is proposed. In this process, ethanol yield on SB-DSY mixed substrates was 0.08 g/g.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Sugarcane bagasse (SB) and dry spent yeast (DSY) were used for ethanol production. </LI> <LI> SB and DSY were converted biologically to a feedstock for ethanol production. </LI> <LI> 8.98 g-ethanol/L, with a yield of 0.46 g/g, was achieved from SB–DSY hydrolysate. </LI> <LI> A bioconversion process for SB and DSY to ethanol, with mass balance, is proposed. </LI> <LI> Under the propose process, ethanol yield was 0.08 g-ethanol/g-mixed-substrates. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>