초록
<P><B>Abstract</B></P> <P>Biochar has functional groups, pH buffering capacity and cation exchange capacity (CEC) that can be beneficial in syngas fermentation. This study examined the properties of biochar made from switchgrass (SGBC), forage sorghum (FSBC), red cedar (RCBC) and poultry litter (PLBC), and their effects on ethanol and butanol production from syngas using <I>Clostridium carboxidivorans</I>. Experiments were performed in 250 mL bottle reactors with a 50 mL working volume at 37 °C fed syngas containing CO:H<SUB>2</SUB>:CO<SUB>2</SUB> (40:30:30 by volume). Results showed that PLBC and SGBC enhanced ethanol production by 90% and 73%, respectively, and butanol production by fourfold compared to standard yeast extract medium without biochar (control). CO and H<SUB>2</SUB> utilization in PLBC and SGBC media increased compared to control. PLBC had the highest pH buffering capacity, CEC and total amount of cations compared with SGBC, FSBC and RCBC, which could have contributed to its highest enhancement of ethanol and butanol production.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Ethanol and butanol production were improved by using medium with SGBC and PLBC. </LI> <LI> 10 and 20 g L<SUP>−1</SUP> loading of PLBC or SGBC significantly enhanced syngas fermentation. </LI> <LI> Biochar’s nutrients and pH buffering reduced acid stress on <I>C. carboxidivorans</I>. </LI> <LI> PLBC has the highest concentrations of Na, K, Ca, Mg, P, S and Mn elements. </LI> <LI> More Ca, Mg, P, Fe, and Mn were released from biochar during syngas fermentation. </LI> </UL> </P>