BioChem - DOS

Metabolic pathway and flux analysis of H2 production by an anaerobic mixed culture

International journal of hydrogen energy

Gonzalez-Garcia, R.A.; Aispuro-Castro, R.; Salgado-Manjarrez, E.; Aranda-Barradas, J.; Garcia-Peñ a, E.I.

<P><B>Abstract</B></P> <P>A metabolic model is proposed for H<SUB>2</SUB> production from a mixed culture growing on glucose. The model based on the metabolism of <I>Firmicutes</I>, predominant phylum, includes substantial changes compared with previous models. Full TCA cycle and a bifurcating dehydrogenase that uses ferredoxin and participates in the reduction of crotonyl-coenzyme-A are introduced. Pathway analysis suggests that H<SUB>2</SUB> yields greater than those reported are possible redirecting the flow of glucose to the pentose phosphate pathway instead of glycolysis. H<SUB>2</SUB> yield as high as 10 mol H<SUB>2</SUB>/mol glucose is metabolically possible if the H<SUB>2</SUB> pressure is sufficiently low. The adequacy was determined by metabolic flux analysis. Experimental yield of 2.23 mol H<SUB>2</SUB>/mol glucose are contained in the solution space and shows that growth is suboptimal for the mixed culture used. Data suggest that H<SUB>2</SUB> yields can be improved by knocking out both competing reactions and the phosphoglucose isomerase. Higher NADPH<SUB>2</SUB> production could increase H<SUB>2</SUB> production even though it would reduce growth rate.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A core metabolic model is presented for H<SUB>2</SUB> production with a mixed culture. </LI> <LI> The model shows that a yield of 10 mol H<SUB>2</SUB>/mol glucose is theoretically possible. </LI> <LI> The pentose phosphate pathway is key for improving H<SUB>2</SUB> yield. </LI> <LI> Knock-out of phosphoglucose isomerase should improve H<SUB>2</SUB> yield. </LI> <LI> MFA reveals a suboptimal metabolism for growth and H<SUB>2</SUB> production on glucose. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

2017

Elsevier

0360-3199

1879-3487

42

7

pp.4069-4082

10.1016/j.ijhydene.2017.01.043

http://click.ndsl.kr/servlet/OpenAPIDetailView?keyValue=05787966&target=NART&cn=NART77528783

H2 production; Metabolic pathway analysis (MPA); Metabolic flux analysis (MFA); Mixed culture