Judul: Characterization of protoxin protein and chitinase enzyme from indigenous isolates Bacillus thuringiensis
Abstrak: Bacillus thuringiensis secreted exochitinase activity when grown in a medium containing chitin. Chitinase and protoxin protein play a important role in the pathogenicity of Bacillus thuringiensis to insect pest. This research was aimed to determined characterization of B. thuringiensis subsp. pakistani indigenous isolates, B. thuringiensis Lot II, and B. thuringiensis 47 to produce chitinase enzyme and protoxin protein. Optimum production of chitinase from B. thuringiensis subsp. pakistani was obtained at 24th hours, pH 7.5, and 40oC. B. thuringiensis Lot II was optimum at 21th hour, pH 6,0, and 50oC. B. thuringiensis 47 was optimum at 21st hour, pH 5,0, and 35 oC. Ammonium sulphate was used for precipitation of chitinase protein. The highest spesific activity of chitinase was obtained on ammonium sulphate at saturation 20% for B. thuringiensis subsp. pakistani, 30% for B. thuringiensis Lot II and 40% for B. thuringiensis 47. The highest production of protoxin protein from B. thuringiensis subsp. pakistani and B. thuringiensis 47 was obtained at 36th hour, whereas B. thuringiensis Lot II at 33rd hour. The molecule weight of chitinase molecule was determined by Sodium Dodecyl Sulfate Solution Polyacrilamide Gel Electrophoresis (SDS-PAGE). Molecular weight of chitinase of B. thuringiensis subsp. pakistani, B. thuringiensis Lot II and 47 estimated at 71,15 kDa. The weight of protoxin protein molecule all isolates estimated 129,99 and 130,04 kDa.
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Judul: Isolasi, Pemurnian Parsial, dan Karakterisasi Enzim Kitinase dari Bacillus sp. BPPT CC 2
Abstrak: Chitinase is a potential enzyme due to its acitvity hydrolyting chitin to its derivates. Therefore, it can be used for various applications, such as agriculture, microbiology, and cosmetic. This study aimed to isolate, purify, and characterize (pH, temperature, metal ion effect, molecular weight, and kinetic parameters) chitinase of Bacillus sp. BPPT CC 2. Ammonium sulphate precipitation and dialysis were used for enzyme purification. Enzyme was characaterized its optimum pH and temperature, metal ions, molecular weight, as well as kinetic parameters. The results showed that enzyme was well precipitated using 80% ammonium sulphate. After dialyzed, level of enzyme purity increased 6.58 fold with specific activity of 0.0924 U/mg. Results showed that the optimum temperature and pH of chitinase were found at 55ºC and pH 5. Value of Km and Vmaks values were 2.705x10-4mg/L second and 0.6959 mg/L. Predicted molecular weight of chitinase was 103 kDa. Addition of metal ions Mn2+and EDTA (5 mM and 10 mM) act as activators of chitinase
Keyword: Bacillus sp. BPPT CC 2, characterize, chitinase, kinetic parameter, purification

Judul: Cycle Hamilton pada Graf Lengkap, Graf Regular, dan Graf 2-Connected 4-Regular Berorder Kurang dari Sepuluh
Abstrak: Suatu graf disebut graf Hamilton apabila graf tersebut memuat cycle Hamilton, yaitu cycle yang melewati setiap vertex tepat satu kali. Menentukan keberadaan cycle Hamilton pada suatu graf dapat menggunakan syarat cukup yang berupa teorema-teorema yang telah diperkenalkan sejak tahun 1950-an. Beberapa syarat cukup yang dibahas dalam karya ilmiah ini adalah syarat cukup yang berhubungan dengan graf lengkap dan graf regular. Suatu graf lengkap berorder 𝑛������ ≥ 3 dan graf r-regular berorder 𝑛������ ≤ 2𝑟������ + 1 merupakan graf Hamilton, Karena kedua graf tersebut memuat cycle Hamilton. Selanjutnya, syarat cukup tersebut digunakan untuk menentukan keberadaan cycle Hamilton pada graf 2-connected 4- regular berorder kurang dari 10.
Keyword: graf Hamilton, graf regular, graf lengkap, graf 2-connected 4-regular