| 摘要 |
PROBLEM TO BE SOLVED: To obtain a nitrous acid reductase, useful for denitrifying supply water and sewage with a bioreactor and capable of converting nitrate ions into nontoxic nitrogen in the presence of oxygen under acidic conditions and removing the nitrate ions. SOLUTION: This nitrous acid reductase having the following properties is obtained by culturing Haloferax denitorificans ATCC35960, etc., (1) catalyzing reaction of NO2 <-> +2H"<+> +e<->→NO+H2 O; (2) optimum pH; 4.8-5.5 and developing activities at pH 4-7; (3) optimum temperature: 40 deg.C and stable at <=45 deg.C; (4) having oxygen resistance retaining the activities for 2 months under aerobic conditions; (5) specifically inhibited with diethyl dithiocarbamate; (6) 127,900 molecular weight (measured by a gel filtration method) and 64,000 molecular weight of its subunit ]measured by a sodium dodecyl sulfate-polyacrylamide gel electrgphoresis (SDS-PAGE)[ and (7) having an absorption band at about 460 and 590nm. |
