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From the flue gas desulfurization system aerobic biological production of sulfur -magnetic steady state fluidized bed reactor to take the magnetic porous beads immobilized biofilm row sulfur thiooxidans medium under aerobic conditions enrichment repeatedly purified from isolates after bacterial colony morphology observed , as well as a series of physiological and biochemical indicators , corresponding Bergey bacterial identification manual , Thiobacillus thiooxidans is a row of sulfur (thiobacillus) ( thiobacillus thioparus ) preliminary identification of the isolates . Row disulfide subtilis cells obtained by the separation and purification ultrasonic crushing, desalted and concentrated , ion exchange chromatography of the DEAE -52 , Sephadex G -150 size exclusion chromatography separated and purified sulfite acceptor oxidoreductase , and its nature characterization. Spectroscopy showed enzyme other features in addition to 280nm outside the absorption peak ; SDS -PAGE and the results show that the enzyme is an αβ heterodimer composed of two subunits of molecular weight 33.9KDa and 42.2KDa ; viability analysis found that 92 % of enzyme activity present in the cell membrane fraction , the enzyme is a membrane protein . The optimum pH is 7.5, the optimal temperature was 40 ° C , the enzyme activity has a good stability within the wide range of pH 3-7.5 , temperature between 3 ° C to -50 ° C enzyme activity can be maintained at more than 70% . The enzyme Vmax sodium sulfite to 22.15μM/min Km of 86.09μM ; substrate specificity and strong , the enzyme is substantially independent of Na K , Mg < sup > 2 , Fe 2 , Fe 3 , Ca 2 , Cu 2 , Zn 2 , Mn 2 and the Ba 2 and other metal ions , EDTA and sodium hydroxide significantly inhibited the enzyme . Its oxidation product as the sulfate. Enzyme activity analysis methods of the enzyme may be involved in the metabolism of sulfur-oxidizing bacteria isolated pathway were measured, and with reference to the relevant literature , there is proposed a possible model isolates sulfur oxidation pathway .
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