Judul: Preservasi Xilanase Bacillus pumilus (PU-4-2) Dengan Teknik Imobilisasi Pada Polard dan Penambahan Kation
Abstrak: Pemanfaatan limbah pertanian sebagai alternatif bahan pakan temak unggas sudah mulai dilakukan, namun pemberian secara langSWlg kurang menguntungkan karena kadar serat yang tinggi. Untuk itu perlu dilakukan upaya penurunan kaOO serat dengan penambahan' enzim hidrolisis, salah satunya enzim xilanase. Penambahan enzim xilanase ke dalam campuran pakan perlu mcmperbatikan sifat cnzim yang tidak stabil dan murlah rusak, sehingga perlu dilakulcan langkah-langkah untuk menjaga stabilitas dad enzim seperti penambahan kation dan imobilisasi. Beberapa enzim sudah diketahui membutuhkan tambahan logam untuk aktivitasnya atau diaktivasi Icbih jauh olch ion logam.
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Judul: Enzim Xilanase Bacillus licheniformis AQ1 : Pemekatan, Studi Termostabilitas, dan Zimogram
Abstrak: Xilan adalah komponen terbesar hemiselulosa pada dinding sel tanaman. Isolat Bacillus licheniformis AQ1 mampu menghasilkan enzim xilanase ekstraseluler bila ditumbuhkan di dalam media yang mengandung xilan. Xilanase isolate AQ1 dapat diendapkan dengan polietilen glikol (PEG) 6000. Waktu paruh xilanase isolat AQ1 pada suhu 500, 600, 700, 800, 900 C dan pH 7 masing-masing sebesar 100.34, 91.22, 83.62, 77.19, dan 71.62 menit. Waktu paruh xilanase isolat AQ1 pada suhu 500, 600, 700, 800, 900 C dan pH 8 yakni sebesar 88.54, 81.36, 75.26, 66.90, dan 61.43 menit. Sedangkan waktu paruh xilanase isolat AQ1 pada suhu 50o, 60o, 70o, 80o, 90oC dan pH 9 yakni sebesar 79.22, 62.71, 60.21, 56.80, 52.81 menit. Berdasarkan hasil uji stabilitas penyimpanan enzim xilanase yang disimpan pada suhu 4oC relatif lebih stabil bila dibandingkan dengan dengan enzim yang disimpan pada suhu ruang (30oC). Analisis zimogram pada gel poliakrilamida dengan konsentrasi 7.5, 10, dan 12% menunjukkan xilanase B. licheniformis AQ1 mampu menghidrolisis substrat oatspelt xylan, beechwood xylan, dan carboxymethyl cellulose (CMC), akan tetapi pita protein yang menunjukkan aktivitas enzim tidak dapat bermigrasi ke dalam gel sehingga bobot molekul protein yang menunjukkan aktivitas xilanase tidak dapat diperkirakan.
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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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