Judul: Isolasi dan Identifikasi Bakteriosin Bakteri Asam  Laktat S12 dari Bekasam
Abstrak: Bakteri asam laktat penghasil bakteriosin diisolasi dari bekasam, makanan tradisional Indonesia dari Provinsi Lampung. Salah satu isolat yang menghasilkan bakteriosin potensial (isolat S12) teridentifikasi sebagai Lactobacillus plantarum S12 berdasarkan sekuen 16S rRNA. Analisis sekuen 16S rRNA menunjukkan homologi sebesar 98% dengan beberapa strain L. plantarum lainnya. Bakteriosin S12 (plantaricin S12) menunjukkan kemampuan menghambat beberapa patogen, terutama Listeria monocytogenes, dan Staphylococcus aureus. Plantaricin S12 yang dihasilkan berasosiasi dengan pola pertumbuhan yang dimulai pada fase awal eksponensial dan mencapai aktivitas maksimum pada fase awal stasioner. Plantaricin S12 cenderung stabil pada suhu tinggi hingga 121 °C selama 15 menit. Bobot molekul plantaricin S12 diperkirakan sekitar 10,79 kDa berdasarkan analisis SDS-PAGE. Selain itu, gen-gen yang menyandi plantaricin S12 diantaranya gen pln EF dan gen pln JK. Plantaricin S12 diperkirakan termasuk bakteriosin kelas II yang memiliki potensi untuk diaplikasikan sebagai biopreservatif pangan.
Keyword: Lactobacillus plantarum, plantaricin S12, SDS-PAGE analysis

Judul: Produksi Bakteriosin Asal Lactobacillus plantarum sebagai Antimikrob dan Pengujian Ketahanannya terhadap Panas
Abstrak: Bacteriocin is commonly used to biopreservative agent in food. Bacteriocin is an antimicrobial substance that is capable to inhibit toward pathogenic and food borne bacteria. It was reported that indigenous isolate of Lactobacillus plantarum isolated from Indonesian local beef producing an antimicrobial substance (Arief et al., 2008). The objective of this research was to characterize the heat stability of plantaricin at pasteurization and sterilization temperature. The treatments were heat temperature (80 °C for 30 minutes and 121 °C for 15 minutes) and strains of Lactobacillus plantarum (2C12, 1A5, 1B1 and 2B2) usage. The variable was diameter of inhibition zone of antagonistic activity. Antimicrobial activity of plantaricin of Lactobacillus plantarum 2C12, 1B1, 2B2, and 1A5 did not lost after treated at 80 °C for 30 minutes or at 121 °C for 15 minutes. That result showed that plantaricin was stable at pasteurization and sterilization temperature. Plantaricin produced by strains of L. plantarum against indicator bacteria such as Pseudomonas ATCC 27853, Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 25922 and Salmonella enteriditis ser. Typhimurium ATCC 14028 had different activity each other. However, inhibition activity of plantaricin did not lead against Bacillus cereus. Stability of antimicrobial activity of plantaricin to inhibit indicator bacteria after heat treatment proved that plantaricin has a potential as food biopreservative.
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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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