Judul: Produksi Xilooligosakarida dari Xilan Tongkol Jagung Menggunakan Enzim Bakteri Streptomyces costaricanus 451-3
Abstrak: Xilanase merupakan kelompok enzim ekstraseluler yang menghidrolisis xilan atau polimer dari xilosa dan xilooligosakarida. Xilanase dapat diklasifikasikan berdasarkan substrat yang dihidrolisis, yaitu β-xilosidase, eksoxilanase, dan endoxilanase. Enzim xilanase dapat dihasilkan oleh mikroorganisme dengan sumber makanan seperti limbah tongkol jagung, limbah sekam padi, tandan kosong kelapa sawit dan kulit kedelai. Salah satu bakteri penghasil enzim xilanase yaitu Streptomyces costaricanus 45I-3.
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Judul: Produksi Dan Karakterisasi Xilanase Mikroba Yang Diisolasi Dari Tongkol Jagung.
Abstrak: Enzim penghidrolisis xilan melibatkan dua tipe utama yaitu endo-β-1,4- xilanase (EC. 3.2.1.8) dan β-xilosidase (EC. 3.2.1.37). Enzim-enzim tersebut bekerjasama menghidrolisis xilan (hemiselulosa) menjadi rantai pendek xilooligosakarida dan xilosa. Xilanase (enzim penghidrolisis xilan) merupakan salah satu enzim yang banyak dimanfaatkan secara luas dalam bidang industri pangan maupun non pangan serta mempunyai dampak positif terhadap lingkungan (clean processing). Xilan (hemiselulosa) yang merupakan substrat xilanase banyak terdapat pada tongkol jagung yaitu sebesar 40 %. Dalam penelitian ini dilakukan isolasi mikroorganisme pendegradasi xilan (hemiselulosa) yang terdapat pada tongkol jagung busuk. Selain itu tongkol jagung itu sendiri dimanfaatkan sebagai substrat kasar (crude) dari mikroorganisme yang diisolasi. Penelitian yang dilakukan merupakan salah satu upaya diversifikasi pemanfaatan produk samping hasil pengolahan jagung. Penelitian dimulai dengan mengisolasi mikroba penghasil xilanase dari tongkol jagung busuk. Dari hasil pemilahan diperoleh 12 isolat mampu menghasilkan clearing zone pada media yang mengandung oat spelt xylan 0.7 %, salah satu diantaranya adalah isolat yang diberi kode MBXiK4 yaitu memiliki indeks xilanolitik cukup tinggi (5.81) dan aktivitas enzim yang tertinggi (5.29 U/ml (pengukuran I), 1.78 U/ml (pengukuran II)). Isolat lokal yang terbaik tersebut digunakan untuk optimasi kondisi produksi enzim, karakterisasi enzim xilanase dan β-xilosidase. Hasil optimasi produksi oleh isolat MBXiK4 menunjukkan aktivitas enzim tertinggi (11.59 U/ml) terjadi pada hari ketiga, konsentrasi tongkol jagung 1%, dengan kondisi pH 7 dan suhu 37oC. Hasil ini tidak berbeda jauh jika dibandingkan dengan menggunakan substrat oat spelt xylan 0.7 % yang menghasilkan aktivitas enzim tertinggi sebesar 11.37 U/ml pada pH 7 dan suhu 37oC.
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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