Judul: Aktivitas Keratinase Bacillus licheniformis dalam Memecah Keratin Bulu Ayam
Abstrak: Tepung bulu ayam sangat potensial dikembangkan menjadi bahan baku pakan sebagai sumber protein, karena kandungan proteinnya tinggi. Namun kendala yang dihadapi adalah kandungan senyawa kreatin yang cukup tinggi. Kreatin merupakan peotein serat, tidak larut dalam air dan sulit dicerna. Rantai peptida dalam keratin terbentuk dalam bentuk pilin atau beliks dan saling berhubungan dengan ikatan disulfida dan ikatan hidrogen. Hal inilah yang menyebabkan kreatin sulit dicerna.
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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: Thermal Characteristics and Dynamics of Tropical Cyclone over Western North Pacific Ocean: A Case Study of Typhoon Songda (Chedeng) 2011
Abstrak: The frequent occasion of Tropical Cyclone (TC) over Western North Pacific (WNP) Ocean lies from 10˚N to 26˚N and 121˚E to 170˚E. Sources of TC development come from warm ocean temperature where latent heat is released during condensation processes and subsequently concentrated in the boundary layer. Relative humidity at 850-700 hPa is responsible to produce the most intense storm. Meanwhile, weak vertical wind shear between 850-200 hPa is one of the dynamical factors that lead to the development of TC. Pressure level of 850-200 hPa is chosen to minimize the thermodynamic effect in the lower troposphere. Typhoon Songda (Chedeng in the Philippines) or TSC lasted from May 18th to 30th, 2011 and strengthened into powerful Super Typhoon stage between May 24th and 27th. Long curving track and the exhibition of all sequences of TC life cycle, TSC is then considered as an ideal case of TC. The objective of the study with case of TSC is to investigate the role of thermal characteristics and dynamics on TC intensity. The research is carried out by using Advanced Research of Weather Research and Forecasting model (WRF ARW model) version 3.3. Two domains are employed in the model. The first domain situate from 02˚N to 40˚N and 118˚E to 149˚E and cover spatial resolution () of 33.1 km. The second domain situate from 09˚N to 27˚N and 119˚E to 132˚E with of 11 km. Timestep of the model () is 120 seconds. The model is supported by the following physical parameterization, i.e., Yonsei University Scheme (YSU) in the boundary layer, Kain-Fritsch scheme (KF) in the cumulus, and WRF Single-Moment 3-class scheme in the microphysics. Initial meteorological condition prior to the formation of the cyclone is generated using WRF ARW standard-release model. Sensitivity of the model output is obtained from a selected single-parameter change scenarios, namely, 10 % to 20 % decrease and increase of wind shear initial data at 850-200 hPa, and by 10 % to 20 % decrease of relative humidity initial data at 850-700 hPa. The result showed that the negative correlations between wind shear and intensity are found in wind shear scenarios. Wind shears of 10 ms-1 which lead to strengthening of the wind intensity in the early period of Typhoon development are found in wind shear scenarios. The effect of wind shear changes on wind intensity is statistically significant in the 20 % wind shear scenarios. During mature stage, weak wind intensity occurred when wind shear increase as given in the WRF standard-release and the 20 % decreasing scenario. Different situation is found in the 20 % increasing scenario where wind shear tend to weak and lead to strong wind intensity at this stage. Meanwhile, the reduction of moisture supply at 850-700 hPa resulting from 20 % decreasing relative humidity play a major role in the weakening of wind intensity and reduces mechanical energy of the cycle process as much as 300 J kg-1.
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