title: Comparison of CO-dependent H₂ production with strong promoters in Thermococcus onnurineus NA1.
abstract: To overproduce biotechnologically valuable products, the expression level of target genes has been modulated by using strong promoters. In a hyperthermophilic archaeon Thermococcus onnurineus NA1, two promoters, P(TN0413) and P(TN0157), which drive expression of the genes encoding the S-layer protein and glutamate dehydrogenase were inserted in front of a gene cluster encoding a carbon monoxide dehydrogenase, a hydrogenase and a Na⁺/H⁺ antiporter. Two promoters exhibited strong activity by increasing the transcription and translation levels of the gene cluster in the mutant strains by 2.5- to 49-folds and 1.4- to 3.3-folds, respectively, than the native promoter in the wild-type strain. While KS0413 with P(TN0413) promoter exhibited 2.7 to 4.7 times higher transcript level than KS0157 with P(TN0157) promoter, the levels of proteins were a little different between them. The biomass concentrations and H₂ production rates of two mutants were 2- to 3-fold higher than those of the wild-type strain in a bioreactor where CO was supplied at a flow rate of 120 ml min⁻¹. Two mutants showed differential response to the higher CO flow rate, 240 ml min⁻¹, in terms of growth pattern and product formation, indicating two promoters were regulated by culture conditions. The results demonstrate that not only promoter strength but also product-forming conditions should be considered in promoter engineering.
authors: Korea Institute of Ocean Science and Technology, Ansan, 426-744, South Korea.
authors: Seong Hyuk
authors: SH
authors: Lee
authors: Min-Sik
authors: MS
authors: Kim
authors: Seung Seob
authors: SS
authors: Bae
authors: Ae Ran
authors: AR
authors: Choi
authors: Jin-Won
authors: JW
authors: Lee
authors: Tae Wan
authors: TW
authors: Kim
authors: Jung-Hyun
authors: JH
authors: Lee
authors: Hyun Sook
authors: HS
authors: Lee
authors: Sung Gyun
authors: SG
authors: Kang
mesh_terms: D000445:Aldehyde Oxidoreductases / Q000235:genetics / Q000378:metabolism; D018533:Biomass; D002248:Carbon Monoxide / Q000378:metabolism*; D006859:Hydrogen / Q000378:metabolism*; D006864:Hydrogenase / Q000235:genetics / Q000378:metabolism; D009097:Multienzyme Complexes / Q000235:genetics / Q000378:metabolism; D011401:Promoter Regions, Genetic; D017923:Sodium-Hydrogen Exchangers / Q000235:genetics / Q000378:metabolism; D019712:Thermococcus / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism*
chemical_list: D009097:Multienzyme Complexes; D017923:Sodium-Hydrogen Exchangers; D002248:Carbon Monoxide; D006859:Hydrogen; D006864:Hydrogenase; D000445:Aldehyde Oxidoreductases; C019823:carbon monoxide dehydrogenase