Judul: Penampisan Bakteri Asam Laktat Asal Berbagai Sumber Bahan Hewani dan Nabati dalam Menghasilkan Bakteriosin
Abstrak: Perhatian dan keprihatinan masyarakat sangat besar terhadap semakin pesatnya penggunaan bahan kimia sebagai pengawet makanan. Dengan pertimbangan untuk keamanan, kesehatan dan mempertahankan kualitas bahan pangan maka konsumen lebih menyukai penggunaan senyawa yang berasal dari komponen hayati sebagai bahan biopreservatif makanan. Spesies tertentu dari BAL menghasilkan bakteriosin yang bersifat antimikrob yang dapat diianfaatkan sebagai biopreservatif makanan untuk mengontrol pertumbuhan bakteri pembusuk dan patogen pada bahan pangan. Tujuan penelitian ini adalah mencari biakan BAL asal becbagai sumber hewani dan nabati lokal yang berpotensi menghasilkan bakteriosin dan menganalisis sifat-sifat bakteriosin tersebut.
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Judul: Production and Characterization of Bacteriocin from Lactobacillus fermentum 2B2 and Its Antimicrobial Activities Against Pathogen Bacteria
Abstrak: Bakteri asam laktat (BAL) yang terdapat secara alami di dalam daging atau susu memiliki kemampuan sebagai bahan pengawet alami karena menghasilkan senyawa antimikroba. Salah satu senyawa antimikroba yang dihasilkan yaitu bakteriosin. Penggunaan bakteriosin sebagai biopreservative sangat menjanjikan karena bersifat bakterisidal atau bakteristatik terhadap bakteri lain khususnya bakteri yang berkerabat dekat dengan bakteri penghasilnya (Vuyst and Vandamme, 1994). Potensi bakteriosin ini meningkatkan penelitian dalam mempelajari dan mendapatkan informasi yang lebih dalam mengenai produksi bakteriosin, purifikasi parsial bakteriosin, konsentrasi penghambatan minimum dalam minimum inhibitor concentration (MIC) dan minimum bactericidal concentration (MBC) terhadap bakteri patogen, serta karakterisasi bakteriosin melalui uji kepekaan bakteriosin terhadap enzim katalase dan proteolitik, Produksi dan Karakterisasi Bakteriosin Asal Lactobacillus fermentum 2B2 dan Aktivitas Antimikrobanya terhadap Bakteri Patogen.
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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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