Thermostable glucoamylase-type enzyme from Bacillus acidocaldarius RP1

We present an experiment that enables student to understand the properties of thermostable glucoamylase-type enzyme produced by thermophilic Bacillus acidocaldarius RP1 isolated from Cimanggu Hot Spring, West Java, Indonesia. In addition, the students also gain experience working with a thermostable microorganism and some techniques frequently used in biochemistry, e.g. ultrasonication, ammonium sulfate fractionation, and spectrophotometric analysis. The glucoamylase-type enzyme activities were detected both as cell-associated and in the culture supernatant. The 20-40% saturated ammonium sulfate fraction of glucoamylase-type enzyme exhibited an optimum temperature of 65 degreesC and an optimum pH of 4.5. The enzyme showed a V-max of 600 milliunits/mg and K-m of 11.7 mg/ml.