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: The Effects of Variance of Interest rate to Variance of Annuity Future Values
Abstrak: Time value of money is a concept that refers to the difference of the value of money due to time difference. The value of money for present time would not be the same as the value of money in the future. The value of money for present time is called as Present Value (PV) of the money and the value of money for future time is called Future Value (FV) of the money. Determination the value of money, for present and future time, depends on the time and rate of return. The value of money is determined by several factors such as inflation, fluctuation of interest rates, and government policy in securities and taxation. Due to fluctuation of the value of money we need a FV formulation, it is useful for knowing whether an investment can be profitable or not, and this information is useful also in budget analysis. Annuity is defined as a series of payments made for a specific period. The payment, fixed or varied, can be made at the beginning or at the end of the period. Annuity paid at the beginning of the period is called annuity-due and annuity paid at the end of the period is called immediate annuity-certain. The accumulated value of the annuity after few years later is called as a final value or a future value. Burnecki et al. (2003) have discussed about the FV of a fixed-rate annuity in which payments are made according to the arithmetic or geometric series. They have also examined FV for annuities in which payments are made according to arithmetic or geometric series with random rates of interest. This paper examines FV for annuity-due in which payments are made according to arithmetic or geometric series with interest rates as a random variable, which is normal distribution ,  . Future value formula is expressed in recursive form. FV for annuity-due which payments are made according to the arithmetic or geometric series with random rates of interest is calculated by theoretical way and simulation way. The random rates of interest is denoted as k k i  i  , where k i an independent random variable; i is a constant and k  is a random variable which has normal distribution ,  . By using the determined parameters, a sequence of random rates of interest are generated for theoretical calculation. Meanwhile for the simulation, the random rates of interest is generated 1000 times for the simulation. The generated data give mean value, variance, and standard deviation. Moreover, error of mean value, variance, and standard deviation from the theoretical and simulation results are calculated. Error calculation uses Symmetric Mean Absolute Percentage Error (SMAPE). The smaller the value of SMAPE is the more accurate the simulation. The interest rate variances are varied from 0.000036 to 0.0001 to study the relationship between variance of rates of interest and variance of future value. The theoretical and simulation results show that when the variance of random rates of interest increases, then the variance of FV increases linearly. FV of the annuity-due in
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