초록
<P><B>Abstract</B></P> <P>Xylose is a by-product of lignocellulosic biomass processing for production of second-generation biofuels and could be suitable for bioproduct manufacturing. This paper describes an innovative approach that enables the system to achieve high yielding for hydrogen production. The study compared 4 physicochemical pre-treatments performed in an anaerobic mixed culture (acidic, thermal, acidic-thermal and thermal acidic) to achieve an inoculum with a high-efficiency xylose to hydrogen conversion under mesophilic conditions (30 °C). The acidic pre-treatment was the most efficient to select microorganisms able to produce hydrogen and volatile acid from xylose. Kinetics has shown that acidic pre-treatment had a hydrogen/xylose molar yielding factor of 1.57 (molar base) and a hydrogen maximum production rate of 253 mL H<SUB>2</SUB> h<SUP>−1</SUP>. Mass balance considered all possible metabolic pathways using xylose as a substrate. Anaerobic degradation of ethanol was the most active pathway for hydrogen production in all experiments, except for the control. Each pre-treatment performed for the original inoculum resulted in different microbiological profiles, but the genus <I>Clostridium</I> was the most abundant in all assays. Acidic pre-treatment stimulated the growth of organisms from the genera <I>Peptostreptococcaceae</I>, <I>Truepera</I> and <I>Kurthia</I>, which could be related to the better results in hydrogen production found in this condition.</P> <P><B>Highlights</B></P> <P> <UL> <LI> H<SUB>2</SUB> production was related to <I>Peptostreptococcaceae</I>, <I>Truepera</I> and <I>Kurthia</I> </LI> <LI> Acidic pretreatment led to a higher, faster and more stable H<SUB>2</SUB> production </LI> <LI> Thermal-acidic pretreatment was ineffective to stimulate H<SUB>2</SUB> production </LI> <LI> All inoculum pretreatments inhibited CH<SUB>4</SUB> production </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>