Judul: Kinetika Selulolitik Isolat Khamir Dari Tanah Gunung Halimun, Jawa Barat
Abstrak: Khamir lebih dikena! sebagai jenis cenrlawan bersel satu, merupakan kelompok mikrob yang jarang diselidiki Khamir menghasilkan enzim untuk membantu proses-proses reaksi dalam tubuhnya, di antaranya selulase. Enzim seJulase menghidrolisis selulosa menjadi glukosa yang digunakan sebagai sumber energi. Penelitian ini menguji aktivitas selulolitik tiga isolat khamir yang berasal dari tanah Gunung Halimun, Jawa Barat. Pengukuran enzim menggunakan substrat selulosa tersubtitusi, yaitu karboksimetil se1ulosa (CMC)_ Tiga isolat khamir, isolat 7, 9, 24 merupakan khamir yang memiliki aktivitas CMC-ase. DaTi ketiga isolat yang diinkubasi pada media pertumbuhan cytophage, hanya isolat 24 yang menunjukkan pertumbuhan baik dalam media pertumbuhan, kondisi stabH, serta memiliki aktivitas CMC-ase tertinggi, yaitu 0.2537 Unit. Aktivitas tertinggi isolat 7 dan 9 masing-masing 0.0194 U dan 0.0238 U. Parameter kinetika yang ditentukan terhadap isolat 24 meliputi uji kinetika pertumbuhan ialah laju pertumbuhan spesjfik maksimum (J.Imw), dan waktu perlipatan-dua sel (1<1). Hasil peneiitian menunjukkan bahwa isolat 24 memiliki nilai Ilmab
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Judul: Pencirian selulolitik isolat khamir, Rhodotorula sp. dari tanah hutan taman nasional gunung halimun
Abstrak: Salah satu spesies khamir (Rhodotorula sp.) yang diisolasi dari tanah hutan Taman Nasional Gunung Halimun telah diuji kemampuan hidupnya pada berbagai media (Cytophage, Yamanobe, dan Srinivassan), berbagai sumber karbon (karboksimetil selulosa/ CMC, avisel, dan kertas saring), dan berbagai pH awal (4.0, 7.0, dan 9.0). Khamir tersebut juga diuji kemampuan selulolitiknnya terhadap CMC, avisel, dan kertas saring. Selain itu, telah dilakukan pula pencirian (pH dan suhu optimum) terhadap enzim aviselase. Uji tersebut dilakukan untuk mengetahui seberapa besar kemampuan selulolitik serta ciri-ciri enzim yang dihasilkan khamir Rhodotorula sp. Hasil penelitian menunjukkan media terbaik untuk produksi enzim selulase adalah media Srinivassan yang memiliki pH awal 4.0, dengan 0.5% avisel sebagai sumber karbonnya. Uji selulolitik Rhodotorula sp. menunjukkan kemampuan khamir ini dalam menguraikan CMC, avisel, dan kertas saring, namun kemampuan khamir ini dalam menguraikan avisel lebih dominan (11.33 U/ml) dibandingkan dengan CMC dan kertas saring. Enzim aviselase memiliki pH optimum 4.8 dan suhu optimum 35°C.
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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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