Judul: Judul Karakterisasi enzim selulase dari kapang laut untuk hidrolisis Gelidium sp. sebagai bahan baku bioetanol
Abstrak: Enzim selulase merupakan enzim yang umumnya diproduksi dari hewan, tanaman, bakteri, protozoa, dan fungi. Enzim selulase yang diproduksi pada penelitian ini berasal dari kelompok fungi yaitu jenis kapang laut. Kapang laut yang diperoleh adalah kapang laut yang diisolasi dari substrat rumput laut Gelidium sp. yang berasal dari Pulau Pari, Kepulauan Seribu, Provinsi DKI Jakarta. Isolat yang dihasilkan diberi kode PGEL 95. Enzim selulase yang diproduksi dari isolat tersebut memiliki karakteristik aktivitas optimum pada pH 7, suhu 30°C, dan waktu aktivitas optimum pada jam ke-60. Aktivitas enzim selulase meningkat dengan penambahan ion logam Ca2+, K+, dan Na+ dengan konsentrasi 10 mM dan menurun dengan penambahan ion Fe3+, Mg2+, dan Zn2+ pada konsentrasi 5 mM. Enzim selulase ini memiliki bobot molekul sebesar 6,73 kDa. Kadar etanol yang diperoleh dari hasil fermentasi dengan enzim selulase adalah 0,25% (v/v) pada suhu 50oC dengan lama fermentasi adalah 5 hari.
Keyword: bioethanol, cellulase, enzyme, seaweed

Judul: Karakteristik dan Aplikasi Enzim Selulase Kasar dari Kapang Laut Untuk Fermentasi Gelidium sp.
Abstrak: Enzim selulase dapat digunakan sebagai penghidrolisis dalam pembuatan bioetanol. Tujuan dari penelitian ini adalah optimasi dan karakterisasi enzim dari isolat kapang dan mengaplikasikan enzim sebagai katalisator dalam produksi bioetanol. Isolat dengan kode A7 dan A13 memiliki aktivitas selulase. Enzim selulase yang diperoleh dari isolat A7 dan A13 masing-masing memiliki aktivitas terbaik pada pH 4,96 dan pH 6. Kedua enzim menunjukkan aktivitas terbaik pada suhu 30 °C dan selama 12 jam waktu inkubasi pada konsentrasi enzim 15% untuk isolat A7 dan 20% untuk isolat A13. Enzim selulase dari kedua isolat memiliki berat molekul 6,73 kDa. Fermentasi menggunakan Saccharomyces cerevisiae pada enzim dari isolat A7 tidak dapat menghasilkan bioetanol, sedangkan enzim dari isolat A13 dapat menghasilkan bioetanol. Bioetanol dihasilkan paling tinggi diperoleh pada fermentasi dengan suhu 40 °C selama 5 hari yaitu sebesar 0,32% (v/v).
Keyword: enzim, etanol, hidrolisis, rumput laut, selulase

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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