초록
<P><B>Abstract</B></P> <P>This study was focused on investigating the potential of hydrogen and volatile fatty acid (VFA) coproduction. Sweet sorghum stalks (SS) were used as substrate along with <I>Clostridium thermocellum</I> and <I>Clostridium thermosaccharolyticum</I> as production microbes. Inoculation ratio of <I>C. thermosaccharolyticum</I> to <I>C. thermocellum</I> (0:1–1.5:1 and 1:0 v/v), substrate concentrations (2.5–15.0 g/L) and inoculation time intervals of <I>C. thermosaccharolyticum</I> followed by <I>C. thermocellum</I> (0–48 h) were investigated. Experimental data showed that higher yields of hydrogen and VFA were obtained in the co-culture than their individual cultures. The optimum conditions for the highest yield of products found as 1:1 inoculation ratio of both strains, 24 h of time gap between <I>C. thermosaccharolyticum</I> followed by <I>C. thermocellum</I> after the first inoculation and 5 g/L of substrate concentration. The maximum yield of products was observed as hydrogen (5.1 mmol/g-substrate), acetic acid (1.27 g/L) and butyric acid (1.05 g/L) at optimum conditions. The results suggest that SS can be used for simultaneous production of hydrogen and VFA employing co-culture of <I>C. thermocellum</I> and <I>C. thermosaccharolyticum</I> strains. This approach can contribute to the sustainability of biorefinery.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Sweet sorghum stalks (SS) are suitable for biohydrogen production. </LI> <LI> Co-culture of themorphilic microorganisms enhances biohydrogen production. </LI> <LI> Co-culture strategy also improves volatile fatty acids production from SS. </LI> </UL> </P>