关键词: 蜡样芽孢杆菌, 亚硝酸盐还原酶, 亚硝酸盐降解, 16S rDNA, 细胞定位

Abstract: A strain LJ01 with strong nitrite degradation ability was isolated from fermented bean paste and was iden-tified as Bacillus cereus． Then，the primary cell localization of this nitrite reductase was examined by measuring the enzyme activity of different cellular components from LJ01 cell． After LJ01 was induced by 100 mg/L sodium nitrite solution and treated with lysozyme，the crude enzyme solution of LJ01 was first separated by means of the anion DEAE Sepharose Fast Flow chromatography，and the nitrite degradation activity of fractions a，b and c was measured． Moreover，by using inorganic electron donors such as 0. 1mol/L succinic acid and sodium sulfite solu-tion，fraction c was identified as a critical nitrite reductase and was separated by Sephadex G-150 column to get pure protein． The identification results show that 0. 54mg of active enzyme protein with an activity of 4004. 89U/mg can be obtained from 1L of the fermentation liquid，and that the specific NiR activity of the purified enzyme increa-ses by 17. 57 folds with a recovery of 2. 37%． In addition，SDS-PAGE results show that the monomer molecular mass of LJ01 is about 30ku．

Key words: Bacillus cereus, nitrite reductase, nitrite degradation, 16S rDNA, cell localization