초록
<P><B>Abstract</B></P> <P>The employment of hemicellulose fractions from bagasse acid (HF-AC - rich in xylose) and hydrothermal (HF-HT - containing high amounts of xylooligosaccharides) pretreatments led to yields of 265 and 177 mL<SUB>H2</SUB>/g<SUB>carbohydrate</SUB> after 18 and 45 h of fermentation, respectively. The anaerobic sludge used as inoculum was able to hydrolyze the xylooligosaccharides of HF-HT into simpler sugars, enabling microbial hydrogen production. The acid hydrolysis of xylooligosaccharides in HF-HT before fermentation improved the productivity by 30% and showed similar yield (231 mL<SUB>H2</SUB>/g<SUB>carbohydrate</SUB>). The adaptive phase for HF-HT consumption was influenced by the hydrolytic step and by inhibitors, as the kinetics of hydrolyzed HF-HT was deeply affected in the first 18 h compared to HF-AC. Higher amounts of HF-AC in the media promoted fermentation inhibition, which could be related to the increased concentrations of acetic acid and carbohydrates, two factors that enhance the system osmolarity.</P> <P><B>Highlights</B></P> <P> <UL> <LI> C5 fractions from acid or hydrothermal pretreatment of sugarcane bagasse were used. </LI> <LI> Oligosaccharides were hydrolyzed into simpler sugars by the anaerobic sludge. </LI> <LI> Hydrolytic step and inhibitors influenced the hydrothermal C5 fraction consumption. </LI> <LI> Total osmolarity of the fermentative media plays a role in H<SUB>2</SUB> production inhibition. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>