초록
<P><B>Abstract</B></P> <P>The aim of this study is to assess the potentials of using mixed culture bacteria incorporated with different concentrations of NaHCO<SUB>3</SUB> for hydrogen production from water hyacinth (WH). The lowest hydrogen yield (HY) of 30.4 ± 1.9 mL/g<SUB>TVS</SUB>, H<SUB>2</SUB> content (HC) of 19.5 ± 1.5% and hydrogenase enzyme (HE) activity of 0.06 ± 0.01 mgM.B<SUB>reduced</SUB>/min were registered for the cultures without supplementation of NaHCO<SUB>3</SUB>. The HY, HC, and HE activity were maximized at levels of 69.2 ± 4.3 mL/g<SUB>TVS,</SUB> 58.4 ± 3.6% and 0.18 ± 0.01 mgM.B<SUB>reduced</SUB>/min. respectively for the anaerobes supplied with 3.0 g NaHCO<SUB>3</SUB>/L. Furthermore, cellulose, hemicellulose, and lignin destruction efficiencies were 37.2 ± 2.3, 30.0 ± 1.9 and 20.9 ± 1.3% respectively due to the increase of cellulase and xylanase activities up to 2.73 ± 0.17 and 1.87 ± 0.12 U/mL, respectively. Moreover, the abundance of <I>Firmicutes</I> was substantially increased and accounted for 71% of the total OTU’s. Microbes belonging to the order <I>Clostridiales and OPB54</I> were particularly enriched in the medium supplemented with NaHCO<SUB>3</SUB>.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Low alkalinity of water hyacinth revealed low H<SUB>2</SUB> productivity. </LI> <LI> NaHCO<SUB>3</SUB> supplementation enhanced H<SUB>2</SUB> production, content, and hydrogenase enzyme. </LI> <LI> Addition of NaHCO<SUB>3</SUB> stimulated higher cellulase and xylanase enzymes activities. </LI> <LI> NaHCO<SUB>3</SUB> incremented the abundance of Firmicutes to 71% of the total OTU’s. </LI> <LI> Net gain energy was augmented to 0.485 ± 0.029 kJ/g<SUB>feedstock</SUB> by the aid of NaHCO<SUB>3</SUB>. </LI> </UL> </P>