Judul: Produksi CMC-ase oleh Aspergillus flavus JPF14 pada Berbagai Substrat Limbah Pertanian
Abstrak: Aspergillus flavus dikenal sebagai fungi penyebab kerusakan pascapanen pada beberapa komoditas pertanian. Kemampuannya dalam mendegradasi selulosa yang merupakan komponen utama penyusun tanaman diduga merupakan hasil dari aktivitas enzim selulolitik yang disekresikannya. Tujuan penelitian ini adalah mendapatkan gambaran produksi CMC-ase yang dihasilkan A.flavus JPF14 pada berbagai substrat limbah pertanian. Limbah yang digunakan sebagai substrat dalam penelitian ini yaitu sekam gandum, sekam padi, dedak, dan TKKS. Aktivitas CMC-ase diuji dengan menggunakan metode Dinitrosalisilat (DNS) dengan mengukur kadar gula pereduksi yang dihasilkan. Produksi CMC-ase optimum terjadi pada kondisi pH 6, suhu 25o C, dan lama inkubasi 48 jam. Indeks selulolitik terbesar 0.4300 ditunjukkan oleh medium substrat sekam padi. CMC-ase optimum diproduksi pada medium fermentasi dedak, yaitu sebesar 0.1492 U/mL.
Keyword: Aspergillus flavus, CMC-ase, limbah pertanian, selulosa

Judul: Produksi Enzim Pektinase oleh Aspergillus ustus pada Media Fermentasi Semi Padat Mengunakan Limbah Pertanian sebagai Substrat
Abstrak: Many types of enzyme are used in food manufacturing process, and pectinase is one of enzyme that is frequently used by many food industries. Pectinase can be fabricated by microorganism through fermentation process using pectin-containing-medium to boost metabolite production. The objective of this research is to determine the substrate from several agricultural wastes and to define the optimum condition of fermentation for pectinase production using Aspergillus ustus (involving substrate concentration, acidity of medium, and temperature of fermentation). There are four steps in this research including substrate preparation, analysis for substrate (pectin measurement and proximate analysis), pectinase production, and trial for optimum fermentating condition. The result shows that difference in fermentating condition will affect the activity of pectinase. The highest pectinase activity is 1.2751 U/mL and it originated from peel of Medanese tangerine. Optimum condition for pectinase production was using peel of Medanese tangerine as substrate in 10% concentration, pH 4, at temperature of 40oC.
Keyword: 

Judul: Dynamical System of Hepatitis B in Three Groups with Vaccination
Abstrak: The aim of this study is to modify the hepatitis B transmission model in three age groups involving vaccination from the model conducted by Zhoe and Zhang.The method used is to analyze the stability of the fixed point and its basic reproduction number (R_0). Performed stability analysis and numerical simulation to see population dynamics. Next, a sensitivity analysis of the parameters was carried out to see its effect on R_0. From the analysis obtained two fixed points, namely non-endemic and endemic fixed points. Non-endemic fixed points are locally asymptotically stable if R_0 <1 Meanwhile, the endemic fixed point is locally asymptotically stable if R_0 > 1. Hepatitis vaccination affects the number of susceptible population, because the more successful the vaccination, the smaller the number of susceptible populations so that the smaller the population will be infected.
Keyword: Dynamic, Hepatitis B, Vaccine, Mathematical model