Judul: Mempelajari Pengaruh Konsentrasi Sel dan Alginat pada Imobilisasi Arthrobacter sp. NRRL B-3728 dengan Metode Penjerapan terhadap Aktivitas Glikosa Isomerase
Abstrak: HFS atau High Fructose Svrup telah banyak diproduksi dengan bahan baku berasal dari jagung, ubi kayu, kentang, beras, ganduni, atau umbi dahlia. Produksi HFS dunia saat ini mencapai sekitar 8 x 10' ketahun (Freeston, 1997) dan konsumsinya telah mengalami peningkatan dari 700 ribu ton pada tahun 1975 menjadi 10.2 juta ton. Pada tahun 2000 ini konsumsi HFS diperkirakan sekitar 13.6 juta ton (Vuilleumier, 1997). Proses pe~nbuatan HFS secara enzimatis melibatkan enzim a-amilase, glukoamilase dan glukosa isomerase. Glukosa isomerase yang - mengkonversi glukosa menjadi fruktosa dapat dihasilkan oleh berbagai mikroorganisme diantaranya Arthrobacter sp. Enzim ini merupakan enzim intraseluler yang umumnya digunakan dalam bentuk terimobilisasi. Penggunaan teknik imobilisasi sel memungkinkan pengurangan biaya untuk pemisahan dan pemurnian enzim. Selain itu, enzim tersebut dapat digunakan berulang-ulang dengan kestabilan yang cukup baik.
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Judul: Mempelajari pengaruh konsentrasi gula (sukrosa) terhadap produksi alginat yang dihasilkan oleh bakteri Pseudomonas aeruginosa
Abstrak: Penelitian ini bertujuan untuk mempelajari pengaruh konsentrasi gula (sukrosa) dan lama inkubasi terhadap produksi alginat yang dihasilkan oleh Pseudomonas aeruginosa. Penelitian ini terdiri atas 2 tahap. Tahap pertama menentukan metoda penyimpanan bakteri dan tahap kedua proses produksi sel yang terdiri dari persiapan bahan, proses fermentasi dan pemanenan. Pengamatan kultur dilakukan setelah kultur berumur 3, 5, 7, 9, 11, 13, 15, 18, 22, 26, 30, 36, 42, 48, 72, dan 96.jam. Parameter yang diukur untuk setiap kali pengamatan adalah konsentrasi alginat, massa sel kering, persentase jumlah sel mucoid dan nonmucoid, residu gula, pH akhir. Selain itu diukur efisiensi konversi nutrien menjadi alginat (Yp/s) dan biomassa (Yx/s) serta efisiensi konversi alginat per biomassa total (Yp/x) dan per biomassa mucoid (Yp/x+) dari kultur. Dari hasil analisa selama inkubasi pada kultur cair, pada medium A (10 g/l), konsentrasi alginat berkisar 0.32-0.85 g/l, massa sel kering berkisar 0.60 -1.57 g/l, persentase jumlah sel mucoid berkisar 10,00-57.14% dan nonmucoid berkisar 42.86 90.00%, residu gula berkisar 2.487.47 g/l, pH akhir berkisar 7-8, nilai Yp/s berkisar 0.0790.857 g produk/g substrat, nilai Yx/s berkisar 0.1942.071 g biomassa/g substrat, nilai Yp/x berkisar 0.112 - 1.164 g produk/g biomassa, dan nilai Yp/x+ berkisar 0.2693.890 g produk/g biomassa. ...
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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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