Judul: Studi denaturasi dan renaturasi protease dari Bacillus pummilus Y1
Abstrak: Enzim Protease sangat besar peranannya sebagai biokatalisator reaksi-reaksi dan proses penting dalam industri, terutama dalam industri pangan. Namun peranannya yang besar tersebut dibatasi oleh kerapuhan struktur proteinnya, yang menyebabkan enzim mudah terdenaturasi dan inaktif. Penelitian ini bertujuan untuk mempelajari kemampuan beberapa bahan kimiawi untuk merenaturasi enzim protease dari Bacillus pumilus Y1 yang sudah terdenaturasi secara kimiawi oleh Guanidin Hidroklorida. Dengan renaturasi diharapkan agar efisiensi penggunaan enzim dapat lebih ditingkatkan. Penelitian ini menggunakan enzim protease dari Bacillus pumilus Y1 yang diisolasi sebelumnya di PAU Bioteknologi IPB, diproduksi dalam media limbah cair tahu dan ditambah skim 0.5%. Denaturasi struktur protein enzim dapat disebabkan oleh lingkungan enzim tersebut seperti suhu, pH, bahan kimia, oksidasi dan hidrolisis proteolisis. Dalam penelitian ini yang dimaksud dengan denaturasi yaitu perubahan konformasi protein enzim, yang mengakibatkan penurunan aktivitas. Untuk studi denaturasi dalam penelitian ini digunakan Guanidin Hidroklorida (Gdn-HCI). Dari penelitian pendahuluan yang telah dilakukan, diketahui bahwa inkubasi dengan Gdn- HCI 1.5 M selama 2 jam dalam buffer borat 0.025 M, dapat menurunkan aktifitas enzim protease Bacillus pumilus Y1 dengan maksimal. Kondisi inilah yang kemudian digunakan lebih lanjut untuk mendenaturasi enzim yang akan digunakan untuk studi renaturasi. Pada proses renaturasi, enzim yang sudah terdenaturasi atau terbuka lipatannya ditambahkan beberapa bahan kimia seperti garam logam, detergen, senyawa polihidroksi dan diberi beberapa perlakuan fisik seperti pengenceran dan dialisis. ...
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Judul: Ekstraksi dan Pemurnian Protease dari Bacilus pumillus (Y1)
Abstrak: Bacillus adalah bakteri yang sangat potensial untuk dijadi kan sumber enzim protease. Bacillus yang digunakan dalam penelitian ini adalah jenis B. pumillus (Y1) yang diisolasi dari limbah cair tahu (Li kumahwa, 1993). Sedangkan penelitian ini bertujuan untuk melakukan ekstraksi dan pemurnian enzim protease dari B. purnillus (Y1 ) dengan menggunakan berbagai kolom kromatografi [DEAE (dietilaminoetil) Sephadex A-50 dan Amberlitel untuk mendapatkan enzim protease yang relatif murni.
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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