초록
<P><B>Abstract</B></P> <P>A simultaneous saccharification and fermentation (SSF) process was applied for thermophilic bio-hydrogen production from lime-pretreated oil palm trunk (OPT) by <I>Thermoanaerobacterium thermosaccharolyticum</I> KKU19. The SSF hydrogen fermentation conditions were optimized to maximize hydrogen yield (HY). Based on Plackett-Burman design, substrate loading and initial pH had significant effects on HY. The substrate loading and initial pH were further optimized using response surface methodology with a central composite design. The optimum conditions were a substrate loading, enzyme loading, inoculum concentration, initial pH and temperature of 4.6%, 10 filter paper unit (FPU)/g-OPT, 10% (v/v), 6.3 and 50 °C, respectively, which yielded the highest HY of 60.22 mL H<SUB>2</SUB>/g-OPT. Structural analysis showed that lime pretreatment and SSF decreased the crystallinity of OPT. Methane production was carried out following the hydrogen production to improve the energy yield from OPT. The results showed that methane production increased total energy yield from 0.65 to 11.79 kJ/g-OPT under the optimal conditions.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Thermophilic SSF proved to be an efficient method for lignocellulose conversion. </LI> <LI> Substrate loading and pH significantly affect thermophilic SSF H<SUB>2</SUB> production. </LI> <LI> Optimal SSF conditions were 4.6% OPT, 10 FPU/g-OPT, 10% inoculum, pH 6.3, 50 °C. </LI> <LI> Hydrogen yield of 60.22 mL/g-oil palm trunk was achieved under optimal conditions. </LI> <LI> Two-stage process enhanced energy yield 18 fold higher than H<SUB>2</SUB> production alone. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>