초록
<P><B>Abstract</B></P> <P>We used metabolic modeling to computationally investigate the potential of bacterial coculture system designs for CO conversion to the platform chemical butyrate. By taking advantage of the native capabilities of wild-type strains, we developed two anaerobic coculture designs by combining <I>Clostridium autoethanogenum</I> for CO-to-acetate conversion with bacterial strains that offer high acetate-to-butyrate conversion capabilities: the environmental bacterium <I>Clostridium kluyveri</I>and the human gut bacterium<I>Eubacterium rectale.</I> When grown in a continuous stirred tank reactor on a 70/0/30 CO/H<SUB>2</SUB>/N<SUB>2</SUB> gas mixture, the C. autoethanogenum<I>-C. kluyveri</I> coculture was predicted to offer no mprovement in butyrate volumetric productivity compared to an engineered <I>C. autoethanogenum</I> monoculture despite utilizing vinyl acetate as a secondary carbon source for <I>C. kluyveri</I> growth enhancement. A coculture consisting of <I>C. autoethanogenum</I> and <I>C. kluyveri</I> engineered in silico to eliminate hexanoate synthesis was predicted to enhance both butyrate productivity and titer. The <I>C. autoethanogenum-E. rectale</I> coculture offered similar improvements in butyrate productivity without the need for metabolic engineering when glucose was provided as a secondary carbon source to enhance <I>E. rectale</I> growth. A bubble column model developed to assess the potential for large-scale butyrate production of the <I>C. autoethanogenum-E. rectale</I> design predicted that a 40/30/30 CO/H<SUB>2</SUB>/N<SUB>2</SUB> gas mixture and a 5 m column length would be preferred to enhance <I>C. autoethanogenum</I> growth and counteract CO inhibitory effects on <I>E. rectale</I>.</P> <P><B>Highlights</B></P> <P> <UL> <LI> CO-to-butyrate conversion with coculture systems was assessed by metabolic modeling. </LI> <LI> The two bacteria performed CO-to-acetate and acetate-to-butyrate conversion. </LI> <LI> <I>Clostridium autoethanogenum</I>/<I>Eubacterium rectale</I> had high butyrate productivity. </LI> <LI> <I>E. rectale</I> inhibition by dissolved CO has a strong effect on predicted performance. </LI> </UL> </P>