초록
<P>Biogas is an attractive renewable energy carrier. However, it contains CO<SUB>2</SUB> which limits its use for certain applications. Here we report a novel approach for removing CO<SUB>2</SUB> from biogas and capturing it as a biochemical through a biological process. This approach entails converting CO<SUB>2</SUB> into biosuccinic acid using the bacterial strain <I>Actinobacillus succinogenes</I> 130Z, and simultaneously producing high-purity CH<SUB>4</SUB> (> 95%). Results showed that when pressure during fermentation was increased from 101.325 to 140 kPa, higher CO<SUB>2</SUB> solubility was achieved, thereby positively affecting final succinic acid yield and titer, CO<SUB>2</SUB> consumption rate, and CH<SUB>4</SUB> purity. When using biogas as the only CO<SUB>2</SUB> source at 140 kPa, the CO<SUB>2</SUB> consumption rate corresponded to 2.59 L CO<SUB>2</SUB> L<SUP>–1</SUP> d<SUP>–1</SUP> with a final succinic acid titer of 14.4 g L<SUP>–1</SUP>. Under this pressure condition, the highest succinic acid yield and biogas quality reached corresponded to 0.635 g g<SUP>–1</SUP> and 95.4% (v v<SUP>–1</SUP>) CH<SUB>4</SUB> content, respectively, after 24 h fermentation. This work represents the first successful attempt to develop a system capable of upgrading biogas to vehicle fuel/gas grid quality and simultaneously produce biosuccinic acid, a valuable building block with large market potential in the near term.</P><P><B>Graphic Abstract</B><BR><IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/esthag/2014/esthag.2014.48.issue-20/es504000h/production/images/medium/es-2014-04000h_0003.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/es504000h'>ACS Electronic Supporting Info</A></P>