Judul: Pemurnian Parsial dan Karakterisasi Beta-Galaktosidase Lactobacillus plantarum B 123
Abstrak: Lactose intolerance was a problem faced by a large proportion of the world's population. These problem could be alleviated by hydrolyzing lactose to glucose and galactose by β-galactosidase. β-Galactosidase occurred widely in nature and it was produced by a number of microorganisms. However, their characteristics were very different and it varied with the source of microorganism. The aim of this study was purification and characterization of β-galactosidase L. plantarum B 123. β-Galactosidase was extracted and partially purified by ammonium sulfate precipitation and dialysis. These steps resulted a purification level of 7.61 fold, a yield of 10.67%, and a specific activity of 61.53 U/mg protein. Optimum temperature and pH for dialyzed β-galactosidase were optimized at 50 °C and 7.0, respectively. Metal ions of Mg2+, Mn2+, Co2+, and Zn2+ in 10 mM stimulated the activity of crude β-galactosidase, while metal ions of Cu2+, Hg2+, and Ca2+ in 10 mM inhibited the activity of crude β-galactosidase. KM and Vmax for this dialyzed β-galactosidase were 1.13 mM and 7.25 U/mL, respectively.
Keyword: Bogor Agricultural University (IPB), characterization, dialysis, Lactobacillus plantarum B 123, β-galactosidase

Judul: Purifikasi Parsial Dan Karakterisasi β-Galaktosidase Dari Isolat Bakteri Asam Laktat (BAL) Strain B134
Abstrak: Lactose intolerance is often occurs in baby, adult, and eldery. It could happen because of the absence of β-galactosidase in gastrointestinal tract. One of solution is β-galactosidase intake from other sources. LAB strain B134 Isolate is a source of β-galactosidase. The aim of the present study was to partial purification and characterization of β-galactosidase from LAB strain B134 isolate. Maximum production of β-galactosidase was obtained when 2% inoculums in MRS that contain 2% lactose, pH: 5, and incubation for 24 hours in 37ºC. Partial purification of β-galactosidase used dialysis. The purification factor, yield, and specific activity of β-galactosidase were found to be 3.313 times, 3.026%, and 45.828 U/mg respective. β-galaktosidase showed higest activity was at pH 6 and temperature 45ºC. Activity of β-galactosidase was stable at pH 4.5 and 30ºC. Cation Co2+, Zn2+, Mn2+, Mg2+ in 0.1 M increased β-galactosidase activity. Meanwhile, Ca2+, Cu2+, and Hg2+ in 0,1 M inhibited β-galactosidase activity. Km and Vmaks of β-galactosidase were 3.934 mM and 3.278 μmol/min.
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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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