Judul: Isolasi Bakteri Selulolitik Dan Karakterisasi Enzim Selulase Dari Feses Kelelawar
Abstrak: Kotoran kelelawar sering dikenal dengan istilah guano. Guano dari kelelawar pemakan buah mengandung lebih dari 60% bahan organik terutama selulosa dan mineral. Guano kelelawar sering dijadikan pupuk oleh masyarakat di sekitar gua. Selulosa yang terdapat di dalam guano dapat didegradasi oleh enzim selulase menjadi gula sederhana, sehingga penyerapan bahan organik oleh tumbuhan lebih optimal. Berdasarkan hal tersebut, diharapkan dapat diperoleh isolat bakteri selulolitik dari feses kelelawar. Tujuan penelitian ini ialah mengisolasi bakteri selulolitik dari feses kelelawar, mengkarakterisasi enzim selulase, serta mengidentifikasi secara molekuler isolat selulolitik terpilih. Hasil isolasi dari dua sampel kotoran kelelawar didapat sembilan isolat dari sampel kotoran kelelawar asal Bogor dan delapan belas isolat dari sampel kotoran kelelawar asal Cirebon. Dua isolat terbaik diperoleh berdasarkan aktivitas enzim selulasenya. Isolat B50 teridentifikasi sebagai Bacillus cereus sedangkan B60 merupakan Bacillus licheniformis berdasarkan uji fisiologi menggunakan kit API 50 CHB. Berdasarkan gen 16S rRNA isolat B50 dan B60 termasuk Bacillus cereus. Aktivitas enzim selulase tertinggi isolat B50 diperoleh sebesar 9.5 mU/mL pada jam ke-24 masa inkubasi. Aktivitas tertinggi enzim selulase pada isolat B60 diperoleh pada jam ke-3 sebesar 17.5 mU/mL. Isolat B50 dipilih untuk dilakukan pemekatan dan karakterisasi enzim selulase. Pemekatan enzim selulase dilakukan dengan menggunakan amonium sulfat. Aktivitas selulase hasil pengendapan memiliki aktivitas yang lebih tinggi dari selulase ekstrak kasar. Hasil pemekatan menunjukkan bahwa selulase isolat B50 mampu mengendap pada konsentrasi 30% jenuh amonium sulfat. Kemurnian enzim hasil pengendapan meningkat sebesar 2.51 kali dengan perolehan sebesar 4.8%. Enzim ekstrak kasar isolat B50 memiliki aktivitas enzim tertinggi dengan menggunakan substrat Carboxymethyl cellulose (CMC) dan hasil pengendapan memiliki aktivitas optimum pada pH 5 dan suhu 40 °C. Selulase hasil pengendapan lebih stabil dibandingkan dengan enzim ekstrak kasar. Hasil SDS-PAGE menunjukkan bahwa bobot molekul dari hasil pengendapan enzim selulase isolat B50 ialah 36.2 kDA. Hal ini dapat disimpulkan bahwa isolat B50 berasal dari feses kelelawar yang hidup di gua Gudawang, Cigudeg, Bogor memiliki aktivitas enzim selulase tertinggi.
Keyword: Bakteri selulolitik, Carboxymethyl cellulose, selulase, guano

Judul: Isolasi, dan karakterisasi bakteri selulolitik asal feses kuda (Equus caballus).
Abstrak: Penelitian ini bertujuan untuk mengisolasi dan karakterisasi bakteri selulolitik asal feses kuda yang diambil dari Equistrian center, Unit Rehabilitasi dan Reproduksi, Sekolah Kedokteran Hewan dan Biomedis Institut Pertanian Bogor (URR SKHB IPB). Penelitian dilakukan dalam tiga tahap. Tahap pertama adalah isolasi bakteri asal feses kuda dengan media N 98-5 dan media selektif selulolitik, tahap kedua dilakukan penapisan bakteri selulolitik dan tahap ketiga uji karaktererisasi isolat terpilih (uji gula-gula pereduksi, uji makroskopis, uji katalase, pewarnaan gram, dan uji aktivitas enzim selulase). Analisis aktivitas enzim menggunakan rancangan acak lengkap (RAL) pola faktorial dengan suhu, pH dan substrat yang berbeda. Suhu yang digunakan ialah 40o C, 50o C dan 60oC, pH yang digunakan ialah 5,6,7,8 serta substrat yang digunakan ialah CMC, Avicel dan Kertas Saring. Hasil penelitian ini di peroleh 3 isolat dengan nilai indeks selulolitik tertinggi yaitu isolat 1 (985.P.K.2.2), isolat 2 (985.P.K.2.3) dan isolat 3 (985.P.K.2.4). Hasil uji karakteriasi menunjukkan ketiga isolat memiliki morfologi yang berbeda. Isolat 2 dan 3, gram positif dan isolat 1, gram negatif. Hasil uji gula-gula pereduksi menunjukkan isolat 1 mampu mereduksi laktosa dan sukrosa, isolat 2 mampu mereduksi laktosa, dan isolat 3 mampu mereduksi sukrosa. Isolat 2 merupakan isolat dengan nilai indeks tertinggi dibandingkan isolat 1 dan 3 serta memiliki aktivitas enzim tertinggi. Hasil uji aktivitas enzim menunjukkan isolat 2 menghasilkan aktivitas terbaik dengan suhu optimum pada suhu 40o C dan pH optimum 5 dengan substrat kertas saring. Disimpulkan bahwa isolat 2, kandidat isolat terbaik dan hasil uji karakterisasi isolat 2 mengarah pada genus dari Bacillus., This study aimed to isolate and characterize cellulolytic bacteria from horse faeces taken from the Equistrian center, Rehabilitation and Reproduction Unit, School of Veterinary Medicine and Biomedical, Bogor Agricultural University (URR SKHB IPB). The research was conducted in three stages. The first stage was the isolation of bacteria from horse feces using N 98-5 media and selective cellulolytic media, the second stage was screening for cellulolytic bacteria and the third stage was the characterization test of the selected isolates (reducing sugar test, macroscopic test, catalase test, gram staining, and cellulase activity). The enzyme activity analysis used a factorial completely randomized design (CRD) with different temperatures, pH and substrates. The temperatures used were 40oC, 50oC and 60oC, the pH used was 5,6,7,8 and the substrates used were CMC, Avicel and filter paper. The results of this study obtained 3 isolates with the highest cellulolytic index value, namely isolate 1 (985.P.K.2.2), isolate 2 (985.P.K.2.3) and isolate 3 (985.P.K.2.4). The results of the characterization test showed that the three isolates had different morphology. Isolates 2 and 3, gram positive and isolate 1, gram negative. The results of the reducing sugar test showed that isolate 1 was able to reduce lactose and sucrose, isolate 2 was able to reduce lactose, and isolate 3 was able to reduce sucrose. Isolate 2 was the isolate with the highest index value compared to isolates 1 and 3 and had the highest enzyme activity. The results of the enzyme activity test showed that isolate 2 produced the best activity at an optimum temperature of 40oC and an optimum pH of
Keyword: bacillus, cellulolytic bacteria, enzyme activity, faeces hourse, fibrobacter

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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