Engineering a hyperthermophilic archaeon, Thermococcus onnurineus NA1, to enhance CO-dependent H2 production

Abstract

The hyperthermophilic archaeon, Thermococcus onnurineus NA1, which was isolated from a deep-sea hydrothermal vent area,can grow on CO as an energy source and produce H2. Previously, we reported that a gene cluster encoding a carbon monoxide dehydrogenase (CODH), a hydrogenase (MCH) and a Na+/H+ antipoter (MNH) was essential for growth and H2 production on CO medium. In this study, we attempted to enhance the expression level of the gene cluster by inserting a strong promoter in front of the gene cluster. Based on the data of proteomic and microarray analyses, two constitutive strong promoters,TN0413 and TN0157, were selected. The resulting KS0413 and KS0157 mutants showed 8 and 2.5-fold higher transcription of the gene cluster than the wild-type strain, respectively. Additionally, H2 production rates of KS0413 and KS0157 mutants measured in a 2L bioreactor were 2 and 4- fold higher than that of the wild-type strain, respectively. This study provides an excellent example of genetic engineering to enhance CO-dependent H2 production in carboxydotrophic microorganisms.xide dehydrogenase (CODH), a hydrogenase (MCH) and a Na+/H+ antipoter (MNH) was essential for growth and H2 production on CO medium. In this study, we attempted to enhance the expression level of the gene cluster by inserting a strong promoter in front of the gene cluster. Based on the data of proteomic and microarray analyses, two constitutive strong promoters,TN0413 and TN0157, were selected. The resulting KS0413 and KS0157 mutants showed 8 and 2.5-fold higher transcription of the gene cluster than the wild-type strain, respectively. Additionally, H2 production rates of KS0413 and KS0157 mutants measured in a 2L bioreactor were 2 and 4- fold higher than that of the wild-type strain, respectively. This study provides an excellent example of genetic engineering to enhance CO-dependent H2 production in carboxydotrophic microorganisms.