Preparation of cell free extract Lysinibacillus sp.
RGS cells were grown in the nutrient broth, pH 6.6 incubated at 30C for 24 h and harvested by centrifuged at
3000 g for 15 min.
These cells (ca. 9.8 g/l) were suspended in potassium phosphate buffer (50 mM, pH 7.4) for sonication (Sonics-vibracell ultrasonic processor), keeping sonifier output at 40 amp and giving 8 strokes each of 40 s with a 2 min
interval at 4C.
After centrifugation of this crude extract at 3000 g for 15 min the supernatant was used as a source of an enzyme. Similar procedures were followed to the cells obtained after complete decolorization (6 h). Protein content was estimated
by the Biuret method.
Protein concentration of cell free extract was kept constant (2.0 mg/ml) for the enzymatic studies.