Judul: Preservasi Xilanase Bacillus pumilus (PU-4-2) Dengan Teknik Imobilisasi Pada Polard dan Penambahan Kation
Abstrak: Pemanfaatan limbah pertanian sebagai alternatif bahan pakan temak unggas sudah mulai dilakukan, namun pemberian secara langSWlg kurang menguntungkan karena kadar serat yang tinggi. Untuk itu perlu dilakukan upaya penurunan kaOO serat dengan penambahan' enzim hidrolisis, salah satunya enzim xilanase. Penambahan enzim xilanase ke dalam campuran pakan perlu mcmperbatikan sifat cnzim yang tidak stabil dan murlah rusak, sehingga perlu dilakulcan langkah-langkah untuk menjaga stabilitas dad enzim seperti penambahan kation dan imobilisasi. Beberapa enzim sudah diketahui membutuhkan tambahan logam untuk aktivitasnya atau diaktivasi Icbih jauh olch ion logam.
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Judul: Amobilisasi xilanase ekstraseluler dari Streptomyces sp. 45I-3
Abstrak: Xilanase mengkatalisis hidrolisis ikatan β-1,4 glikosidik pada xilan menjadi oligomer dan xilosa. Pemecahan sempurna xilan memerlukan aktivitas sinergis dari endo-1,4-β-D-xilanase, 1,4-β-D-xilosidase, Ekso-1,4-β-D-xilosidase, α-D-glukuronidase, α-L-arabinofuranosidase, asetil xilan esterase, ferulil serta kumaroil esterase. Enzim xilanolitik memiliki potensi yang besar untuk diaplikasikan pada berbagai proses industri. Amobilisasi enzim memiliki kelebihan dibandingkan dengan enzim bebas yaitu dapat meningkatkan stabilitas enzim, mengurangi biaya pemakaian enzim, memudahkan pemisahan enzim dari produk dan larutan reaksi sehingga dapat menghentikan reaksi dengan cepat (atau vice versa), mengurangi masalah effluen, dapat digunakan berulang, dapat digunakan dalam proses sinambung, serta dapat digunakan dalam pengembangan sistem reaksi multienzim. Tujuan penelitian ini adalah untuk amobilisasi dan karakterisasi xilanase amobil yang dihasilkan oleh Streptomyces sp. 45I-3 asal Kalimantan. Amobilisasi xilanase dilakukan dengan menggunakan matriks larutan EudragitTM S100 1 % (b/v) dengan rasio volume antara xilanase dan EudragitTM S100 1 % (b/v) adalah 5:1. Karakterisasi xilanase amobil dilakukan dengan menentukan pH optimum pada kisaran 3.0–7.0 dan suhu optimum pada kisaran 30–70 oC, mengukur stabilitas termal pada suhu 30–70 oC selama 1 jam, mengukur stabilitas pada xilan birchwood dan xilan tongkol jagung selama 7 jam, mengukur stabilitas pada suhu 40 oC dan pH 5.0, hidrolisis xilan birchwood dan xilan tongkol jagung, serta penggunaan berulang xilanase amobil. Hasil penelitian ini menunjukkan bahwa xilanase amobil mengalami penurunan aktivitas menjadi 23.97%, memiliki pH dan suhu optimum pada 6.0 dan 40 oC, memiliki stabilitas pada suhu 30–40 oC, pH 6.0 selama 1 jam, stabil pada xilan birchwood dan xilan tongkol jagung selama 6 jam pada pH 6.0 dan suhu 40 oC, serta lebih stabil pada xilan birchwood dibandingkan xilan tongkol jagung. Xilanase amobil stabil selama 5 jam pada suhu 40 oC dan pH 5.0. Spesifitas xilanase amobil terhadap xilan birchwood menghasilkan DP antara 37 – 7, dan pada xilan tongkol jagung antara 122 – 26. Xilanase amobil dapat digunakan berulang, namun terjadi penurunan aktivitas menjadi 52.38% setelah 3 kali penggunaan. Xilanase amobil memiliki potensi untuk diaplikasikan pada pembuatan beragam xilooligosakarida.
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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