Investigating the effect of different genetically modification of Escherichia coli for hydrogen production by means of metabolic engineering

The importance of hydrogen production is that it is a promising fuel since it has 3_ fold higher energy content compared to oil (142 MJ kg⁻¹ for H₂ versus 44 MJ kg⁻¹ for oil), is arenewable fuel and the products of hydrogen oxidation are only water and energy. Glucose is one of the most important substrates for hydrogen production because of its highhydrogen content and its abundant availability in the form of biomass. This research aimsto enhance hydrogen production by E. coli from glucose by manipulating its metabolic pathways via targeted deletions. According to recent studies more hydrogen production canbe arisen due to introducing these gene knockouts; ldhA, frdABCD, poxB, adhE, adhC to BW25113 hyaB hybC hycA fdoG/ Pca24N_ fhlA E.coli strain along with modified pseudogene ydfW in which glucose metabolism would be directed to pyruvate formatelyase (PFL) and producing organic acids in dark fermentation dramatically could reduced. Two methods were used in this study; (i) FLP recombinase and P1 transduction, (ii) usingcharacteristic primers and restriction enzymes beside using of the isogenic E.coli K-12 KEIO library and EcoGene database, in this way the multiple precise mutations could be introduced into a single strain. The result was more than141 fold increase in biologicalhydrogen production that was observed in BW mutant, so that hydrogen yield from glucose with quite could closed to the theoretical yield of hydrogen. Hence our approach appears to be more robust than these earlier E.coli methods and now the engineered E.coli strain possess more than 113±12 μmol. mg⁻¹. h⁻¹ H₂ production rate.

کلیدواژه ها:

Genetically modification ، Biohydrogen production ، Metabolic engineering ، Novel strain