초록
<P><B>Abstract</B></P> <P>This study concerns the in-house development of enzymes from <I>Aspergillus fumigatus</I> and their application in separate hydrolysis and fermentation (SHF) processes for bioethanol production from pretreated rice straw. The cellulase and hemicellulase activities of <I>A. fumigatus</I> cultivated in NaOH-pretreated rice straw were much higher than those of <I>A. fumigatus</I> cultivated in raw rice straw. <I>A. fumigatus</I> cultivated in raw rice straw exhibited no lignin-degrading manganese peroxidase (MnP) or laccase enzymatic activity. However, <I>A. fumigatus</I> cultivated in NaOH-pretreated rice straw exhibited high lignin-degrading MnP and laccase enzymatic activity. <I>A. fumigatus</I> completely degraded 1.0% NaOH-pretreated rice straw, yielding 27.89 g/L reducing sugar upon loading of 50 g/L rice straw (based on the original amount of rice straw that went to pretreatment). Saccharification of 1.0% NaOH-pretreated rice straw using 200 FPU/mL crude enzyme released 22.15 g/L reducing sugars in 20 h. The SHF processes resulted in an ethanol concentration and yield of 9.45 g/L and 83.5%, respectively, with <I>Saccharomyces tanninophilus</I>.</P> <P><B>Highlights</B></P> <P> <UL> <LI> <I>Aspergillus fumigatus</I> produces all the enzyme components required for biomass hydrolysis. </LI> <LI> <I>A</I>. <I>fumigatus</I> enzymes were evaluated for application in SHF for bioethanol production. </LI> <LI> The SHF processes resulted in an ethanol concentration and yield of 9.45 g/L and 83.5%, respectively. </LI> <LI> Bioethanol can be obtained efficiently and inexpensively with addition of only 10 g/L (NH<SUB>4</SUB>)<SUB>2</SUB>SO<SUB>4</SUB>. </LI> <LI> Lignin-degrading enzymes are very important for reducing sugar and bioethanol production. </LI> </UL> </P>