초록
<P><B>Abstract</B></P> <P>Sugarcane bagasse was pretreated with sodium carbonate, sodium sulfite, and sodium acetate in concentrations of 0.5 M and 0.25 M, as well as hydrothermal pretreatment, to break down its structural recalcitrance and improve biogas and ethanol production. The pretreatments were conducted at 100, 140, and 180 °C for 1 h. The highest biogas and ethanol production was observed for sugarcane bagasse pretreated with 0.5 M sodium carbonate solution at 140 °C, which was 239 ± 20 Nml CH<SUB>4</SUB>/g VS, and 7.27 ± 0.70 g/l, respectively, containing gasoline equivalents of 164.2 ± 14.3 l/ton of raw bagasse and 147.8 ± 14.2 l/ton of raw bagasse, respectively. The highest gasoline equivalent was obtained for biogas production from the substrate pretreated with 0.5 M sodium sulfite solution at 100 °C (190.2 ± 2.1 l/ton of raw bagasse). In comparison to sodium carbonate and sodium sulfite, sodium acetate had less effect on biofuel production and was comparable with hydrothermal pretreatment. In contradiction to sodium acetate pretreated bagasse, in which increased pretreatment temperature intensified biofuel production, a reduction of biofuel production was observed for sodium carbonate and sodium sulfite pretreatment when temperature was increased from 140 to 180 °C. Besides considerable amounts of biofuel production at the best conditions obtained, over 762 and 543 kilotons of equivalent CO<SUB>2</SUB> can be reduced annually in Iran by biogas and ethanol production from sugarcane, respectively.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Na<SUB>2</SUB>CO<SUB>3</SUB> and Na<SUB>2</SUB>SO<SUB>3</SUB> pretreatments effectively enhanced ethanol and biogas production. </LI> <LI> CH<SUB>3</SUB>COONa pretreatment was less effective than that with Na<SUB>2</SUB>CO<SUB>3</SUB> and Na<SUB>2</SUB>SO<SUB>3</SUB>. </LI> <LI> Pretreatment 140 °C with 0.5 M Na<SUB>2</SUB>CO<SUB>3</SUB> solution enhanced biogas production by 339%. </LI> <LI> Solid recovery was important in maximum gasoline equivalent achievement. </LI> <LI> 543 kton reduction in CO<SUB>2</SUB> emission in Iran occurs with ethanol production from bagasse. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>