초록
<P><B>Abstract</B></P> <P>The utilization of the juice from the cheapest carbon source oil palm frond (22 $/ton) in a 3.5 L bioreactor was proven to be competent in replacing pure sugar in succinic acid production. The current study provides an in-depth discussion on the utilization of CO<SUB>2</SUB> in the production of succinic acid. In the serum-bottle fermentation, the yield of succinic acid increased by 51% from 0.47 to 0.71 g/g while the final titer of succinic acid enhanced by 4 fold were attributed to the anaplerotic reaction of <I>Actinobacillus succinogenes</I> and the alkalinity effect of the dissolved CO<SUB>2</SUB>. In the bioreactor, the highest mass transfer in the fermentation medium was achieved at 0.5 vvm CO<SUB>2</SUB> at which 3 M KOH was pumped in at a rate of 2.0 mL/min to neutralize the carbonic acid formation, which afforded the highest succinic acid concentration of 30.7 g/L. A first report on actual stoichiometry equation relating substrate, CO<SUB>2</SUB> consumption and all products formation was derived from the results of bioreactor fermentation to lay as a guideline for future reference of actual succinic acid production reaction. C<SUB>6</SUB>H<SUB>12</SUB>O<SUB>6</SUB> + 0.145 NH<SUB>3</SUB> + 0.642 CO<SUB>2</SUB> → 1.083 C<SUB>4</SUB>H<SUB>6</SUB>O<SUB>4</SUB> + 0.509 CH<SUB>2</SUB>O<SUB>2</SUB> + 0.420 C<SUB>2</SUB>H<SUB>4</SUB>O<SUB>2</SUB> + 0.117 C<SUB>2</SUB>H<SUB>5</SUB>OH + 0.726 CH<SUB>1.8</SUB>N<SUB>0.2</SUB>O<SUB>0.5</SUB> + 0.614 H<SUB>2</SUB>O. Actual stoichiometry equation revealed that for every kg of succinic acid produced, 0.22 kg of CO<SUB>2</SUB> will be absorbed. The desirable effect of CO<SUB>2</SUB> on the production of succinic acid may translate into a mutually-beneficial relationship between the succinic acid and the CO<SUB>2</SUB>-generating biofuel industries.</P> <P><B>Highlights</B></P> <P> <UL> <LI> CO<SUB>2</SUB> utilization in fine chemical succinic acid production. </LI> <LI> Oil palm frond as cheap alternative carbon source in succinic acid production. </LI> <LI> Mutually-beneficial of bio-based succinic acid and CO<SUB>2</SUB>-producing biofuel industries. </LI> <LI> Actual succinic acid stoichiometry equation relating all product and byproducts. </LI> <LI> Alkalinity of CO<SUB>3</SUB> <SUP>2−</SUP> ions as pH buffer and CO<SUB>2</SUB> supplier for succinic acid production. </LI> </UL> </P>