title: Increased Production of Food-Grade d-Tagatose from d-Galactose by Permeabilized and Immobilized Cells of Corynebacterium glutamicum, a GRAS Host, Expressing d-Galactose Isomerase from Geobacillus thermodenitrificans.
abstract: The generally recognized as safe microorganism Corynebacterium glutamicum expressing Geobacillus thermodenitrificans d-galactose isomerase (d-GaI) was an efficient host for the production of d-tagatose, a functional sweetener. The d-tagatose production at 500 g/L d-galactose by the host was 1.4-fold higher than that by Escherichia coli expressing d-GaI. The d-tagatose-producing activity of permeabilized C. glutamicum (PCG) cells treated with 1% (w/v) Triton X-100 was 2.1-fold higher than that of untreated cells. Permeabilized and immobilized C. glutamicum (PICG) cells in 3% (w/v) alginate showed a 3.1-fold longer half-life at 50 °C and 3.1-fold higher total d-tagatose concentration in repeated batch reactions than PCG cells. PICG cells, which produced 165 g/L d-tagatose after 3 h, with a conversion of 55% (w/w) and a productivity of 55 g/L/h, showed significantly higher d-tagatose productivity than that reported for other cells. Thus, d-tagatose production by PICG cells may be an economical process to produce food-grade d-tagatose.
authors.affiliation: Department of Bioscience and Biotechnology, Konkuk University , Seoul 05029, South Korea.
authors.forename: Kyung-Chul
authors.initials: KC
authors.lastname: Shin
authors.affiliation: Department of Bioscience and Biotechnology, Konkuk University , Seoul 05029, South Korea.
authors.forename: Dong-Hyun
authors.initials: DH
authors.lastname: Sim
authors.affiliation: Department of Bioscience and Biotechnology, Konkuk University , Seoul 05029, South Korea.
authors.forename: Min-Ju
authors.initials: MJ
authors.lastname: Seo
authors.affiliation: Department of Bioscience and Biotechnology, Konkuk University , Seoul 05029, South Korea.
authors.forename: Deok-Kun
authors.initials: DK
authors.lastname: Oh
mesh_terms: D001709:Biotechnology / Q000379:methods; D018914:Cells, Immobilized; D048230:Corynebacterium glutamicum / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D003470:Culture Media / Q000737:chemistry; D005690:Galactose / Q000378:metabolism*; D056506:Geobacillus / Q000201:enzymology* / Q000235:genetics; D006207:Half-Life; D006601:Hexoses / Q000096:biosynthesis*; D006863:Hydrogen-Ion Concentration; D017830:Octoxynol / Q000737:chemistry; D010539:Permeability; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D013549:Sweetening Agents / Q000378:metabolism; D013696:Temperature
chemical_list: D003470:Culture Media; D006601:Hexoses; D011994:Recombinant Proteins; D013549:Sweetening Agents; D017830:Octoxynol; C030192:tagatose; D005690:Galactose
keywords: Corynebacterium glutamicum; GRAS microorganism; Geobacillus thermodenitrificans; d-galactose isomerase; d-tagatose; immobilized cells; permeabilized cells