초록
<P><B>Abstract</B></P> <P>In this study, we investigated four conventional pretreatments under pressurized conditions, as well as <I>in situ</I> detoxification using polyethylene glycol (PEG 400), for the simultaneous saccharification and fermentation (SSF) of green coconut fibers. The highest fermentable sugar production (22.05% g/g untreated fiber) was reached with pressurized dilute alkaline pretreatment. In the SSF, the addition of PEG favored ethanol production compared to that in experiments without the polymer, reaching a maximum value of 7.87 g/L at a liquor content of 50% v/v for the pressurized water pretreatment. After lignin recovery by acid precipitation, the liquors had interesting antioxidant properties, similar to those of fruit extracts. The proposed pressurized water pretreatment could be an advantageous choice because it can be performed at mild temperatures (70 °C) and high solid loadings (26.67% w/v) and achieves a high mass yield (72.84% w/w) without the addition of a chemical agent. Furthermore, the liquor can be used in the SSF, reducing the water consumption and number of steps in the cellulosic ethanol process.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Pretreatment at mild temperature and high solid loading was successfully performed. </LI> <LI> Pressurized alkaline pretreatment allowed the greatest structural change in biomass. </LI> <LI> Liquors showed high concentration of sugar and bioactive components. </LI> <LI> Simultaneous saccharification and fermentation was improved by PEG 400. </LI> <LI> Ethanol yield reached 87% using biomass and liquor from hydrothermal pretreatment. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>