Characterization of an Enzyme Capable of Degrading the Sheath of the Sphaerotilus natans from Terrabacter sp. FK3 = Characterization of an Enzyme Capable of Degrading the Sheath of the Sphaerotilus natans from Terrabacter sp. FK3

다국어 초록 (Multilingual Abstract)

A microorganism for biological control of sludge bulking was isolated from soil. The isolated microorganism was able to degrade the sheath of the Sphaerotilus natans causing a bulking of activated sludge. The isolated strain, FK3, was identified as a Terrabacter species by analysis of its 16S rRNA genetic sequence. Glucose (0.1%, w/v) and 0.1% yeast extract as carbon and nitrogen sources, respectively, were used in the medium for Terrabacter sp. FK3 growth and enzyme production. Sheath-degrading crude enzyme was purified from a Terrabacter sp. FK3 culture broth via ultrafiltration, followed by DEAE-cellulose chromatography. Although the enzyme activity was optimal at pH 8 and 30$^{\circ}C$, the enzyme maintained stable activity below 50$^{\circ}C$ and in the pH range from 5-10. Sheath-degrading enzyme activity was accelerated by addition of $Mg^{2+}$, $Ca^{2+}$, and $Fe^{2+}$, but inhibited by addition of $Ag^{2+}$ or $Hg^{2+}$. Catalysis was additionally promoted by addition of hydroxyurea, sodium azide, and iodoacetic acid, but inhibited by EDTA.