Judul: Kondisi Pertumbuhan Optimum Bakteri Lactobacillus brevis LIPI13-2-LAB131 dalam Memproduksi Enzim β- galaktosidase
Abstrak: Mikroorganisme potensial sebagai penghasil enzim β-galaktosidase adalah Lactobacillus brevis LIPI13-2-LAB131. Bakteri ini menghasilkan aktivitas enzim β-galaktosidase sebesar 7.93 U/mL. Penelitian ini bertujuan mengoptimalkan kondisi pertumbuhan Lactobacillus brevis LIPI13-2-LAB131 agar menghasilkan aktivitas enzim β-galaktosidase yang maksimum. Penelitian ini terdiri dari pelaksanaan optimasi proses menggunakan aplikasi design expert 7.00 (DX7) dengan metode response surface methodology (RSM) dan purifikasi parsial enzim β-galaktosidase. Hasil penelitian menunjukkan kondisi pertumbuhan Lactobacillus brevis LIPI13-2-LAB131 optimum pada kombinasi kadar laktosa sebesar 1.48%, suhu 34.91 oC, waktu 48.48 jam, dan jumlah inokulum 2.83% dengan nilai desirability sebesar 0.839. Hasil purifikasi parsial enzim menunjukkan nilai aktivitas enzim β-galaktosidase meningkat menjadi 22.88 ± 0.29 U/mL dengan yield hasil purifikasi sebesar 11.65%.
Keyword: enzim β-galaktosidase, kondisi pertumbuhan, Lactobacillus brevis LIPI13-2-LAB131, optimasi, RSM

Judul: Studi Potensi dan Purifikasi Parsial Enzim β- Galaktosidase dari Isolat Bakteri Asam Laktat Asal Produk Pangan Terfermentasi.
Abstrak: Enzim β-galaktosidase berperan dalam pemecahan laktosa menjadi glukosa dan galaktosa. Enzim ini digunakan dalam industri pangan untuk produkproduk rendah laktosa. Enzim β-galaktosidase bisa berasal dari beberapa sumber, seperti hewan, tumbuhan, ataupun mikroorganisme. Tujuan penelitian ini adalah untuk mempelajari potensi β-galaktosidase dari beberapa isolat bakteri asam laktat dan melakukan purifikasi parsial terhadap enzim dengan aktivitas spesifik tertinggi. Terdapat delapan isolat bakteri asam laktat yang diuji potensinya dalam menghasilkan enzim β-galaktosidase. Isolat 11M106-2 yang telah diidentifikasi sebagai Lactobacillus farciminis memiliki aktivitas spesifik β-galaktosidase tertinggi sebesar 13.90 ± 0.57 U/mg protein. Purifikasi parsial terhadap crude enzim dilakukan melalui dua tahapan, yaitu pengendapan dengan ammonium sulfat kemudian dilanjutkan dengan proses dialisis. Purifikasi parsial terhadap crude enzim isolat 11M106-2 meningkatkan aktivitas spesifiknya menjadi 19.65 ± 0.57 U/mg protein setelah pengendapan dengan ammonium sulfat dan menjadi 75.65 ± 0.64 U/mg protein setelah dilakukan proses dialisis.
Keyword: bakteri asam laktat, β-galaktosidase, laktosa, purifikasi parsial

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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