earticle

영어

Citrobacter amalonaticus Y19 (CAY19) was isolated from anaerobic sludge digester. The facultative anaerobe has fermentative metabolism and is tolerant to about 40% CO. CAY19 has unique capability to oxidize CO with reduction of protons to produce H2gas. None of the other Citrobacter species is reported to have CO induced H2 production. To get a deeper insight of the water-gas shift reaction, genome of CAY19 was explored. From the contiguous gene analysis it was found that apart from the metabolic genes for catabolic pathway of hexose sugars, unique genes for hydrogen production are present. Carbon monoxide dehydrogenase (codh) gene cluster (3.8 kb) was found on contig CAY00120. The hydrogenase (hyd) gene cluster (8 kb) was structurally found to be in the reverse direction with respect to codh cluster on contig CAY00120. Functional analyses of genes suggest that the CODH and hydrogenase proteins in Y19 are closely related to other type IV CODH and Ni-Fe hydrogenases. In this study, we report the first genetic evidence of CO induced H2 production in Citrobacter. The high hydrogen productivity (27.1 mmol/g cell h) can have direct ramifications on H2 industry. The in-depth genetic analysis can provide clue about nature’s ability to engineer microbes by way of adaptive evolution.