Judul: Isolasi dan Seleksi Bakteri Selulolitik Termofilik dari Kawah Air Panas Gunung Pancar, Bogor
Abstrak: Cellulase has important roles in paper, textile, food, and detergent industries. Application of cellulase in industries requires the cellulase to be active and stable at high temperature. Exploration of thermophilic bacteria from crater of hot spring is one of way to obtain thermostable cellulase. The aim of this research was to isolation thermophilic bacteria which has cellulolytic activity from White and Red Crater of Mount Pancar. Cellulolytic activity was determined by ability of bacteria to degrade carboxymethyl cellulose (CMC) substrate. Cellulolytic bacteria was selected based on clear zone which form surrounding the colonies. Cellulase activity was measured by dinitrosalisilic acid (DNS) method. Growth pattern of cellulolytic bacteria was determined. Results showed that bacterial isolates from White and Red Crater of Mount Pancar able to produce cellulase. There were 8 colonies (KP1, KP2, KP3, KP4, KP5, KP6, KP7, and KP10) from white crater and 1 colony (KM1) from red crater showing ability to degrade CMC. KP4 isolate had the higest diameter ratio of clear zone and enzyme activity ( 3.8 and 6.11 x 10-3 U/mL) than KM1 isolate (1.7 and 1.17 x 10-3 U/mL). Both isolates had same growth pattern.
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Judul: Isolasi dan Identifikasi Bakteri Termofilik Penghasil Selulase dari Kelapa Sawit (Elaeis guineensis)
Abstrak: Cellulase is an enzyme catalyzing hydrolysis of cellulose which usually consists of endoglucanases (EC.3.2.1.4), exoglucanases (EC.3.2.1.91) and β-glucosidases (EC.3.2.1.21). Cellulase is a very important enzyme due to its numerous industrial applications. The aim of this research were to isolate and identify cellulase-producing thermophilic bacteria that can be used to increase value added in oil palm industries. Samples of soil, empty fruit bunch compost and palm kernel meal were collected from oil palm plantation for obtained thermophilic bacteria. The samples were screened of cellulase-producing thermophilic bacteria by using a Congo Red method were made on carboxymethyl cellulose (CMC) agar plates. The bacterial cultures were incubated in a shaking incubator (140 rpm) at 50oC for 24 hours. The assay for the enzymatic activity was based on the release of glucose that was detected using 3,5-dinitrosalicylic acid (DNS). In this research, 19 isolates of bacteria were isolated. It was found that 11 isolates of bacteria showed positive results with clear zone around the cultures by using Congo Red method. The result showed that isolates for CK1, EM4 and CK3 possesed the highest enzyme activity of 13.56, 12.50 and 10.49 U mL-1 for cellulase was detected at pH 7, respectively. The results of strain identification based on 16S rRNA showed that strain CK1, EM4 and CK3 were identified as Bacillus subtilis.
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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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