Judul: Isolasi Bakteri Amilolitik Asal Pupa Sutra Attacus atlas dan Karaterisasi Amilasenya
Abstrak: Amylase is one of an enzyme that controls of the world enzyme market, beside it enzyme plays an important role in various industries in Indonesia. The demands of amylase are quite large and have high economic value. Therefore, sources of the enzyme are needed. Microorganism is one of the producer of extracellular enzymes. The materials used in this study were Attacus atlas’s larva and pupas. The purpose of this study was to isolate amilolytic bacteria from Attacus atlas’s larva and pupas, and to characterize the amylase enzyme that is produced by the selected bacterial isolates. Isolation is done by using media that were added inducer of 1% starch. 12 bacteria were obtained from sick pupas, healthy pupas, sick caterpillars and healthy caterpillars, which will be measured amylolytic index. Selected six amylolytic isolates which had the highest index that will used to the next experiment. Isolates USK 1 and 8, had the highest specific enzyme activity that is equal to 0.285 U / mg protein and 0.40 U / mg protein. The result of enzyme characterization showed isolates USK 1 had a temperature optimum at 30°C, pH optimum of 5, with the increased consistency of enzymes, and produced a metaloamilase enzyme. The optimum condition of isolates USK 8 amylase included 30 °C and pH 4. The amylase was catagorised metalloamylase. Identification is only performed on selected isolates the USK 1 using Microgen Bioproduct (physiological testing). The identification of bacterial isolates USK 1 showed that the bacteria is a rod-shaped Burkholderia pseudomallei, which is Gram negative, and pathogenic.
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Judul: Karakterisasi amilase dari isolat bakteri lokal MII 10
Abstrak: Pati yang banyak dihasilkan oleh tumbuhan tingkat tinggi, terdiri dari dua komponen yaitu amilosa dan amilopektin. Amilosa merupakan polimer linier dari sekitar 1000 unit D-glukosa dengan ikatan a-1,4 glikosidik dan beberapa percabangan ikatan a-1,6 sedangkan amilopektin memiliki lebih banyak percabangan. Enzim yang mampu menghidrolisis ikatan a-1,4 glikosidik pada pati disebut enzim amilolitik atau amilase (a- amilase, ß-amilase, dan glukoamilase). Amilase tersebut sangat dibutuhkan untuk industri makanan, minuman, dan tekstil. Kebutuhan impor enzim untuk industri di Indonesia pada tahun 1995 mencapai 4.693.400 dolar Amerika (BPS, 1996). Dalam penelitian ini dilakukan karakterisasi amilase kasar yang dihasilkan bakteri isolat lokal MII10 hasil isolasi Balai Penelitian Bioteknologi Tanaman Pangan, Bogor. Karakter-karakter yang dimaksud meliputi kondisi katalitik optimum (pH dan suhu), kestabilan enzim, kinetika enzimatik, bobot molekul, serta sifat dan perilaku inhibisi dan aktivasinya terhadap beberapa senyawa kimia. Bakteri MII10 yang ditumbuhkan pada suhu 38°C menggunakan substrat pati sagu mampu menghasilkan amilase kasar (Amilase MII10) dengan aktivitas sebesar 53860,65 Unit/ml. Satu unit aktivitas amilase didefinisikan sebagai sejumlah enzim yang dapat menghasilkan 1 mmol gula reduksi (standar maltose) per menit. Dari pengujian aktivitas pada pH reaksi 4,0; 5,0, 6,0; 7,0; 8,0 dan 9,0 diketahui bahwa pH optimum Amilase MII, dicapai pada pH 7,0. Sedangkan penentuan suhu reaksi optimum, dilakukan dengan mengukur aktivitas enzim pada suhu reaksi 30°C, 40°C, 50°C, 60°C, dan 70°C. Dari pengujian tersebut diketahui suhu aktivitas optimum Amilase MII10 adalah 50° 60°C. ...
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Judul: Hamiltonian formulation for linear waves motion in two layers fluid
Abstrak: The surface wave could be considered as a wave that separates two fluids, namely water and air. Based on this assumption, it is introduced the interfacial wave, a wave between two layers of fluid with different density. The formulation of interfacial waves motion begins with deriving the base equation of irrotational ideal fluid. Furthermore, according to irrotational fluid assumption, the base equation can be stated in velocity potential. In this derivation, the fluids domain is assumed to be restricted by rigid lid boundary conditions, both at the upper and lower limit. Therefore, the interfacial waves motion can be explained in a hamiltonian formulation. In the hamiltonian formulation, total energy is defined as the sum of kinetic and potential energy. The hamiltonian system is obtained from reduction of kinetic energy by using the Dirichlet Neumann Operator. The resulted kinetic energy equation is nonlinear. Therefore, this form is linearized by first part of the Taylor expansion. This linearization gives a dispersion relation of linear wave. Based on this dispersion relation, the phase speed of the linear wave depends on the density ratio of the two layers fluid.
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