초록
<P><B>Abstract</B></P> <P>Biological sequestration of CO<SUB>2</SUB> for generating value added products is an emerging strategy. Succinic acid (SA) is an important C4 building block chemical, and its biological production via CO<SUB>2</SUB> sequestration, holds many practical applications. This study presents an in-depth insight on SA production using isolated strain belonging to genus <I>Citrobacter</I>, more closely related to <I>Citrobacter amalonaticus</I> by considering critical process parameters such as different carbon sources at various initial concentrations, buffering agent (NaHCO<SUB>3</SUB>) concentrations and different pH conditions. The effect of H<SUB>2</SUB> gas as an electron donor and availability of CO<SUB>2</SUB> during SA production was also evaluated. The results from this work demonstrated that the isolated strain depicted the ability to utilize diverse carbon sources and highest SA production was achieved with sucrose as a substrate, indicating that reduced carbon substrates help in maximizing the redox potential. Incorporation of CO<SUB>2</SUB> and H<SUB>2</SUB> not only enhanced the production of SA but also affected the total acids profile favoring the production of SA over lactic, formic and acetic acids. Additional supply of CO<SUB>2</SUB> and H<SUB>2</SUB> led to maximum SA production of 12.07 gL<SUP>−1</SUP>, productivity of 0.36 gL<SUP>−1</SUP> h<SUP>−1</SUP> and SA yield of 48.5%. In control operation when no gases were supplied and in other test conditions where either of the gases were supplied, lactic acid was the major end product followed by acetic acid. The positive effect of CO<SUB>2</SUB> for SA production provides scope for sustainable integration of SA and the CO<SUB>2</SUB>-generating biofuel industries or industrial side streams.</P> <P><B>Highlights</B></P> <P> <UL> <LI> CO<SUB>2</SUB> availability contributed for enhanced production of succinic acid (SA). </LI> <LI> Use of CO<SUB>2</SUB> for SA production provides scope for integration to industry side streams. </LI> <LI> First study on SA as major end product by <I>C</I>. <I>amalonaticus</I> </LI> <LI> H<SUB>2</SUB> gas as electron donor had regulatory influence on SA production </LI> <LI> Buffering agent concentration enhances SA production and maintains pH of system. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>