Judul: Isolasi dan Karakterisasi Bakteri Lipolitik dari Oncom
Abstrak: Oncom merupakan makanan fermentasi tradisional dari Jawa Barat yang dibuat menggunakan kapang Neurospora sp. pada oncom merah dan Rhizopus sp. pada oncom hitam. Kandungan lemak dalam bahan pembuatan oncom yaitu ampas tahu atau bungkil kacang tanah memiliki potensi sumber untuk menyaring bakteri lipolitik yang unik. Penelitian ini bertujuan mengisolasi dan mengkarakterisasi bakteri lipolitik dari oncom merah dan hitam, serta mengukur aktivitas enzim lipasenya. Oncom yang digunakan pada penelitian ini berasal dari pengrajin oncom di Kecamatan Leuwiliang, Kabupaten Bogor, Jawa Barat. Hasil penelitian menunjukkan bahwa oncom hitam mengandung total populasi bakteri 9.2x109 cfu g-1, sedangkan oncom merah sebesar 5.6x107 cfu g-1. Total bakteri lipolitik oncom hitam sebesar 1.8x108 cfu g-1 lebih tinggi dibandingkan total bakteri lipolitik yang ditunjukkan oncom merah sebesar 5.0x106 cfu g-1. Dua belas isolat bakteri lipolitik berhasil diperoleh. Tiga isolat yang memiliki aktivitas lipase terbesar yaitu B702, B704, dan B705 dengan nilai aktivitas masing-masing sekitar 3.75 U/mL, 3.75 U/mL, dan 4.00 U/mL. Berdasarkan analisis 16S rRNA menunjukkan ketiga isolat B702, B704, dan B705 memiliki kemiripan dengan Staphylococcus hominis subsp. novobiosepticus strain GTC 1228. Namun, isolat tersebut menunjukkan hasil negatif pada uji hemolisis darah.
Keyword: oncom, bakteri lipolitik, 16S rRNA

Judul: Microbial Population and Morphology of Mold, Yeast, and Lactic Acid Bacteria from Red Oncom and Black Oncom Bogor
Abstrak: Oncom merupakan pangan fermentasi kapang yang terdiri dari dua jenis, yaitu oncom merah dan oncom hitam, yang dibuat dengan menggunakan kapang dan bahan baku yang berbeda. Umumnya, oncom merah terbuat dari ampas tahu dengan kapang Neurospora sitophila, sedangkan oncom hitam terbuat dari bungkil kacang tanah dengan kapang Rhizopus oligosporus dan/atau Mucor. Penelitian ini bertujuan mengetahui populasi mikroba dan karakteristik morfologi dari isolat kapang, khamir, serta bakteri asam laktat yang berasal dari oncom yang diperoleh dari industri yang berbeda. Evaluasi juga dilakukan terhadap tekstur dan pH sampel oncom. Sampel yang dianalisis berasal dari tiga industri oncom merah dan dua industri oncom hitam di Bogor. Kelima industri oncom ini memiliki metode produksi yang berbeda-beda. Hasil analisis menunjukkan bahwa populasi mikroba oncom hitam lebih tinggi dibandingkan oncom merah. Oncom merah mengandung total mikroba 7,5–9,2 log CFU/g; total kapang dan khamir 6,0–7,2 log CFU/g; bakteri asam laktat (BAL) 7,2–8,4 log CFU/g; Enterobacteriaceae 7,0–8,7 log CFU/g; dan spora bakteri 2,8–6,1 log CFU/g. Sementara pada oncom hitam terdapat total mikroba sebesar 9,6–10,1 log CFU/g; total kapang dan khamir 8,0–8,8 log CFU/g; BAL 9,2–10,0 log CFU/g; Enterobacteriaceae 7,0–8,8 log CFU/g; dan spora bakteri 2,2–2,6 log CFU/g. Berdasarkan morfologi kapang, pada oncom merah terdapat Neurospora sp., Mucor sp., Acremonium sp., dan Cladosporium sp., sedangkan pada oncom hitam terdapat Rhizopus sp., Neurospora sp., Geotrichum sp. dan Penicillium sp.. Kapang Neurospora sp. terdapat pada kedua jenis oncom. Oncom merah menunjukkan tekstur yang lebih lunak dari pada oncom hitam, dengan nilai tingkat kekerasan berada pada kisaran 14,93–22,42 mm/5 detik, sedangkan nilai tingkat kekerasan pada oncom hitam sebesar 7,78–13,85 mm/5 detik. Ketiga sampel oncom merah memiliki nilai pH pada kisaran 5,41–5,84. Sementara nilai pH sampel oncom hitam S4 dan S5 sebesar 6,18 dan 4,71., Oncom is a mold fermented food consisting of two types, i.e., red oncom and black oncom, which are made using different molds and raw materials. Generally, red oncom is made from solid waste of tofu with Neurospora sitophila, while black oncom is made from peanut press cake with Rhizopus oligosporus and/or Mucor. The research objectives were to determine the microbial population and morphological characteristics of the isolates of mold, yeast, and lactic acid bacteria obtained from oncom samples and evaluate the texture and pH value of oncom samples. The samples are analyzed from three red oncom industries and two black oncom industries in Bogor. These five oncom industries have different production methods. The results of the analysis showed that total microbial count of black oncom was higher than red oncom. Red oncom contains total microbes, mold and yeast, lactic acid bacteria (LAB), Enterobacteriaceae, and bacterial spores were in the range of 7.5–9.2 log CFU/g, 6.0–7.2 log CFU/g, 7.2–8.4 log CFU/g, 7.0–8.7 log CFU/g, and 2.8–6.1 log CFU/g, respectively. Meanwhile, black oncom contains total microbes, mold and yeast, LAB, Enterobacteriaceae, and bacterial spores were in the range of 9.6–10.1 log CFU/g, 8.0–8.8 log CFU/g, 9.2–10.0 log CFU/g, 7.0–8.8 log CFU/g, and 2.2–2.6 log CFU/g. Based on mold morphology, red oncom contained Neurospora sp., Mucor sp., Acremonium sp., and Cladosporium sp., while black oncom contained Rhizopus sp., Neurospora sp., Geotrichum sp., and
Keyword: oncom hitam, oncom merah, pH, profil mikroba, tekstur

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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