Judul: Pemanfaatan Tetes Tebu dalam Pembuatan Gum Xanthan dengan Menggunakan Inokulum Xanthomonas campestris NRRL B - 1459 dan Asam Glumatat sebagai Sumber Nitrogen
Abstrak: Tetes tebu merupakan hasil samping industri gula yang penting dan dihasilkan dalam jumlah yang cukup besar. Kandungan gulanya yang tinggi memungkinkan untuk dirnanfaatkan sebagai bahan baku untuk menghasilkan produk-produk yang bernilai ekonomis tinggi seperti gum xanthan., Penelitian ini dibagi menjadi dua tahap yaitu penelitian pendahuluan (penentuan perlakuan untuk pemurnian es tebu, penentuan waktu propagasi dan fermentasi) dan penelitian lanjutan. Untuk menentukan perlakuan pendahuluan yang diperlukan, dilakukan fermentasi menggunakan tetes tebu (1)tanpa perlakuan, (2)tetes tebu yang dipucatkan dengan arang aktif satu kali, (3) tetes tebu yang dipucatkan dengan arang aktif tiga kali dan (4)tetes tebu yang dipucatkan dengan arang aktif dilanjutkan dengan dekationisasi dan deanionisasi dengan resin penukar ion (ion exchanger). Pada penelitian lanjutan dilakukan fermentasi dengan tiga taraf konsentrasi gula (30 gll, 40 gll dan 50 gll) dan tiga taraf konsentrasi asam glutamat (5 inM, 15 rnM dan 25 inM). Pengamatan dilakukan terhadap pH cairan fennentasi, viskositas cairan fermentasi, rendemen xanthan, konsentrasi biomassa, efisiensi pemanfaatan substrat dan produktivitas sel dan viskositas larutan gum yang diperoleh.
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Judul: Optimasi Konsentrasi Limbah Cair Tahu Untuk Produksi Gum Xantan Oleh Xanthomonas Campestris
Abstrak: Xanthomonas campestris memiliki kemampuan untuk memproduksi gum xantan yang banyak diaplikasikan sebagai stabilizer, pengemulsi, pengental, dan zat tambahan dalam pengeboran minyak. Biaya dalam proses produksi gum xantan perlu ditekan, salah satunya dengan mengganti sumber nitrogen dengan limbah cair tahu. Penelitian ini bertujuan menentukan konsentrasi optimum limbah cair tahu yang dapat menghasilkan rendemen gum xantan tertinggi. Konsentrasi limbah cair tahu perlu dioptimasi karena kelebihan nitrogen dapat bersifat inhibitor pada proses pertumbuhan dan produksi gum xantan. Konsentrasi limbah cair tahu yang digunakan dalam penelitian ini adalah 20%, 40%, 60%, 80%, dan 100% yang diperoleh dari pengenceran limbah cair tahu awal.Total nitrogen diukur dengan metode Kjeldahl dan diperoleh total nitrogen pada konsentrasi limbah cair tahu 100% sebanyak 0.030%. Biomassa sel dan bobot gum xantan tertinggi dihasilkan pada konsentrasi limbah cair tahu 80%. Biomassa sel tertinggi terukur pada jam ke-48 sebesar 0.33 g/L dan rendemen gum xantan tertinggi terdapat pada jam ke-80 sebesar 1.53 g/L.
Keyword: Biomassa sel, gum xantan, limbah cair tahu, total nitrogen

Judul: Characteristic of Overshooting Top (OT) Based on  Himawari  8  Satellite  as  a  Convective  Cloud  Feature  that  Generates  Extreme Weather in the Java Island Region
Abstrak: Overshooting Top (OT) is a feature at the top of a convective cloud that is associated with extreme weather. Research on OT in tropical Indonesia is still very limited. The existence of geostationary satellites with wide area coverage and fast frequency observations is useful for observing the fast dynamics of the OT life cycle. Therefore, this study intends to analyze the relationship between OT and extreme weather, updraft and thermodynamic conditions of OT when extreme weather occurs, the best objective method for detecting OT in the day time and night time, and the spatiotemporal distribution of OT in the tropical region of Java Island during the 2018-2021 period. Based on visual analysis using visible channel and Himawari 8 sandwich products, 87% of extreme weather events in Java were accompanied by the appearance of OT. It indicates that the presence of the OT pattern is a convection cloud pattern or feature that is closely related to extreme weather events for the Java Island region. The existence of a time lag between the appearance of OT and extreme weather events on Java Island indicates that the OT of convection cloud can be used as a precursor or nowcasting for the appearance of extreme weather. Most of the convective cloud OT features during extreme weather events on Java Island have altitude that were only able to exceed the altitude of the equilibrium level and few were able to exceed the tropopause level of 9 km – 16 km. The difference in atmospheric conditions during extreme weather events on Java Island, which is in the tropics and subtropics, is a strong and unstable convective energy condition characterized by a larger CAPE, as well as unstable KI, LI, SI and TTI values. It is offset by kinematic factors in the form of a weak vertical wind shear (bulk wind shear 0-6 km) and a higher freezing point height. The difference between extreme weather events in the Java Island region and other tropical regions compared to subtropical regions is the strong updraft speed of convection clouds. The IRW Texture COMB algorithm based on the IRW-Texture Gradient modification and the COMB algorithm shows a significant increase in quality for detecting OT and non-OT pixels in Java. Rainy days with rainfall > 50 mm/day are very common in areas with an altitude of > 500 m. On the other hand, the level of convection activity which is indicated by the presence of OT and lightning is significantly reduced in this area. OT of convective clouds appear more frequently during the DJF season and less frequently during the JJA season. OT often appears during the day time and rarely at night time. Most OTs appear in the central part, away from the south and north coasts of Java Island during the day, while OTs that appear near the south and north coasts of Java Island can appear in the morning or afternoon.
Keyword: convective clouds, extreme weather, Overshooting Tops, Himawari 8 Satellite