Judul: Pemurnian dan Karakterisasi Enzim Keratinase dari Bacillus sp. BE-1
Abstrak: The keratinase studied in this research is an extracellular protease produced by Bacillus sp. BE-1. Feather meal substrates were prepared from native chicken feather, treated by sodium hydroxide at temperature of 1000C for 15 minutes to render crude keratinase extract. The crude keratinase was then purified by 2 steps of coloumn chromatography which are Hydrophobic Interaction Chromatography (HIC) and Gel Filtration Chromatography (GFC). Butyl Sepharose (HIC) increased keratinase activity to 67-fold. Further purification using Sephacryl S200-HR (GFC) increased keratinase activity up to the range of 116-515 fold. The highest specific activity of the keratinase was 35,9 U/mg with feather meal as substrate. This keratinase can be completely inhibited by ethylene diamine tetra acetic acid (EDTA). Additon of Mn2+ increased this keratinase activity significantly (about 51-fold) while Mg2+ increased the activity slightly (about 3-fold). Zymogram analysis resulted in that the purified keratinase consisted of two proteases with molecular weight 82 kDa and >97 kDa.
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Judul: Study on keratinase and disulphide reductase activity from Bacillus sp. MTS in keratin degradation
Abstrak: Keratin is insoluble and very stable protein. The disulphide bonds, hydrogen bonds and hydrophobic interaction within the polypeptide gives mechanical strength and also resistance to some protease enzyme. The main objective of this research was to study degradation of native chicken feather by keratinolytic enzymes from Bacillus sp., that is the role of keratinase and disulphide reductase, and this was conducted in four steps. The first step was conducted to select Bacillus sp. which produced extracellular keratinase and disulphide reductase. The isolates used were B. licheniformis MB-2 and Bacillus sp. MTS. The first isolate was a thermophillic bacterium screened from hot springs water of Mount Tompaso-Manado and the latter was mesophillic bacterium from sulphuric soil of Mount Tangkuban Perahu- Bandung. The result showed that Bacillus sp.MTS was more effective than B.licheniformis MB-2 for chicken feather degradation. A minimum medium which contained mineral salts was the best medium for Bacillus sp.MTS to secrete disulphide reductase, while the best medium for keratinase production was minimum medium with addition of 0.02% tripton and 0.02% yeast extract. Bacillus sp.MTS was found to secrete intracellular and extracellular keratinase and disulphide reductase and it was selected for further study. The second step was conducted to characterize the crude keratinase and disulphide reductase of Bacillus sp.MTS . The optimum temperature for keratinase and disulphide reductase were 55oC and 28oC respectively. Optimum pHs for keratinase were 8.0, 10.0 and 11.0, and optimum pH for disulphide reductase was 9.0. SDS-PAGE analysis of the culture-free cell showed 17 – 60 kD protein bands. Zymography analysis of ammonium sulphate fraction (50% w/v) showed that Bacillus sp.MTS secreted multy fraction keratinases of 17, 25, 32, 53, 96 and > 97 kD. The 25 kD keratinase was the most stable enzyme at pH 8.0-11.0 and temperature 55-900 The third step was to purify keratinase and disulphide reductase. Purification with ammonium sulphate 50% (w/v), dialysis, Butyl sepharose FF chromatography dan Sephacryl S-200HR chromatography could increase keratinase and disulphide purities, and gave six active keratinase with specific activity of 10 to 37 U/mg and three active disulphide reductase with specific activity of 30 to 64 U/mg. SDS-PAGE analysis of the highest activities of keratinase fractions showed molecular weights of 53, 32 and 17 kD. The highest activities of disulphide reductase fractions showed of 29 and 17 kD molecular weight. The purified keratinase and disulphide reductase had optimum activity at alkaline pHs (8.0-12.0). C while the 32 and 53 kD fractions were found as unstable. In the fourth step the role of disulphide reductase, reducing agent (DTT and BMT) and urea in hydrolysis of native chicken feather and sheep wool and NaOH prehydrolized chicken feather were studied. The activity of purified keratinase was increased by the presence of purified disulphide reductase.
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Judul: Peramalan Inflow Bulanan DAS Saguling Berdasarkan Curah Hujan Bulanan
Abstrak: DAS Citarum merupakan DAS yang penting bagi kehidupan masyarakat dan industri, khususnya di Jawa Barat. Waduk Saguling merupakan bagian dari DAS Citarum yang terletak di bagian hulu yang mempunyai peranan yang cukup penting, sebagai daerah takaran hujan yang paling luas dari DAS Citarum. Besarnya inflow pada sungai sangat dipengaruhi oleh hujan yang terjadi di lokasi tersebut. Adanya variasi curah hujan baik pengaruh global maupun pengaruh lokal akan menyebabkan adanya anomali aliran. Hal ini perlu diantisipasi agar dampaknya tidak merugikan masyarakat. Karena itu peramalan curah hujan di daerah DAS Saguling diharapkan dapat membantu dalam membuat perencanaan pengelolaan air pada waduk Saguling dan DAS Citarum. Hasil interpolasi pola curah hujan bulanan DAS Saguling terlihat adanya sifat siklik (berulang) dan tren. Berdasarkan ini, peramalan (forecast) curah hujan menggunakan metode Box-Jenkins. Dengan adanya sifat kausal antara curah hujan dan inflow, maka inodel regresi antara curah hujan hasil peramalan dan inflow digunakan untuk melakukan peramalan inflow. Model ini dibandingkan dengan model fungsi transfer. Model peramalan ARIMA, regresi, dan fungsi transfer menggunakan data tahun 1986-2001, sedangkan evaluasinya menggunakan data tahun 2002. Hasil analisis komparatif menunjukkan adanya hubungan erat antara curah hujan dengan inflow bulanan DAS Saguling. Curah hujan langsung dikonversi menjadi inflow untuk bulan tersebut sebesar 68 persen, sedangkan sisanya (32%) berkontribusi nyata pada inflow bulan berikutnya. Model ARIMA (1,0,0)(1,0,1)12Yt merupakan model paling optimum dalam meramalkán curah hujan bulanan bagi DAS Saguling, dengan nilai bias sebesar 88.769 dan MAPE sebesar 498.04. Model regresi Y₁ = 0.257 + 0.45 X, + 0.369 X1 + ARIMA (10,1,2) (1,0,1) 12 a, dapat meramalkan inflow bulanan DAS Saguling dengan kesalahan sebesar 46.7, MSE sebesar 283.993, dan MAPE sebesar 182.121. Model fungsi transfer (2,1,0) dapat meramalkan inflow lebih baik daripada model regresi, dengan kesalahan peramalan lebih kecil daripada model regresi, yaitu sebesar 38, dengan MSE sebesar 158.5 dan MAPE sebesar 147.7.
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