Isolation and Identification of Konjak Decomposing Bacterium No. 215 and Some Properties of the Enzyme Produced by the Strain

Abstract

A bacterium which produced the enzyme hydrolyzing konjak was isolated and characterized. This strain was identified as Bacillus circulans. The B. circulans No. 215 grew favorably in F medium composed of konjak, sodium phosphate, magnesium sulfate and ammonium sulfate, in comparison with H medium which was only made up of konjak. The strain was able to grow in F medium in the pH range 5.5-10.5, and grew most favorably in the pH 6.0 to 9.5 region. Viscosity of F medium decreased rapidly at the initial stage of the cultivation, while reducing sugar in the culture medium was accumulated with the increase of cell population. The properties of the crude konjak-decomposing extracelluar enzyme from this strain were as follows: the optimum temperature was 30°C and the optimum pH range was between 6.4 to 7.2. The enzyme was stable for 40min at 55°C. On thin layer chromatogram of the degradation products of knojak in the culture medium, the spots of glucose, mannose and other products of knojak in the culture medium, the spots of glucose, mannose and other products were detected.