Judul: Biotransformasi Piroka Tekol Menggunakan Kultur Suspensi Sel Solanum Mammosum L.
Abstrak: Tanaman merupakan sumber utama senymva-senyawa kimia yang digunakan terutama untuk industri farmasi. Sclain itu sel tanaman merupakan sumber enzim yang dapat digunakan untuk proses biotransformasi dalam mensintesis senyawa organik tertentu, antara lain senyawa glukosida. Pirokatekol merupakan salah satu senyawa turunan polifenol yang umumnya terdapat dalam buah-buahan dan sayuran telah lama dikenal memiliki aktivitas sebagai antibakteri, antioksidan, antimelanogenesis, antimutagen, dan antihipertensi, akan tetapi senyawa polifenol bukanlah senyawa yang stabil terhadap pengaruh oksidasi, cahaya, dan perubahan kimia. Oleh sebab itu, untuk meningkatkan kestabilan dan kelamlan senyawa polifenol, dapat dilakukan dcngan cara mengubah senyawa tersebut menjadi senyawa dalmn bentuk glikosida, melalui reaksi transglikosilasi dengan metode sintesis kimia, enzimatik, maupun menggunakan metode kultur sel tanaman.
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Judul: Kinetika biotransformasi suksinonitril menjadi asam suksinat oleh Pseudomonas sp.
Abstrak: Asam suksinat (HOOC(CH2)2COOH) merupakan senyawa komersial yang banyak digunakan dalam bidang pangan, misalnya pada industri kecap, sari buah, anggur, dan produk-produk susu lainnya. Selama ini asam suksinat yang kita gunakan dihasilkan melalui serangkaian reaksi kimia yang sangat berbahaya sehingga diperlukan alternatif baru yang lebih aman dan murah melalui proses biotransformasi dengan memanfaatkan aktivitas Pseudomonas sp. Untuk mengetahui kemampuan Pseudomonas sp. dalam proses biotransformasi digunakan sistem fermentasi batch untuk menentukan pola pertumbuhan, perubahan pH, produksi amonium, laju penguraian substrat, dan pembentukan produk. Analisis terhadap penguraian suksinonitril dan asam suksinat yang terbentuk menggunakan kromatografi cair kinerja tinggi yang menggunakan metanol 80% sebagai fase gerak, fase diam kolom organik C18 10 , dan detektor ultraviolet yang diukur pada panjang gelombang 220 nm, sedangkan amonium yang terbentuk diukur dengan menggunakan spektrofotometer pada panjang gelombang 400 nm. Hasil penelitian menunjukkan produksi optimum enzim terjadi pada fasa log. Laju pembentukan asam suksinat sebesar 0.982 mM/mL.jam seiring dengan penurunan konsumsi substrat sebesar 1.235 mM/mL.jam. Perolehan asam suksinat setelah 81 jam fermentasi sebesar 81 %. pH optimum, temperatur optimum, Km, dan Vmaks adalah 7, 27 °C, 90 mM, dan 0.0002 µM/mL.jam.
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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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