Judul: Karakterisasi Enzim Nitril Hidratase Dan Amidase Dalam Sel Corynebacterium D5
Abstrak: Senyawa nitril seperti asetonitril, akrilonitril merupakan senyawa penting dalam industri yang sccara konvensional mempunyai banyak kendala seperti kondisi sintesis yang sui it diatuf, adanya produk samping, dan biaya yang tinggi. Industri enzim akan masalah Iingkungan menyebabkan teknologi enzim sebagai alternatif guna menggantikan proses kirni~}vi dalam sintesis senyawa organik dan pengolahan limbah. Salah satu alternatif adalah secara inikiobiologis, yaitu biokonversi yang lebih ekonomis karena kondisi yang lebih mudah diatur se~ramah ·lingkungan karena dibasilkan produk dengan tingkat kemumian yang tinggi. Pada penelitian ini ditentukan sejumlah karakter yang meliputi senyawa penginduksi enzim, spesifisitas, kondisi optimum, yaitu pH dan subu, serta pengaruh ion logam terhadap aktivitas enzim nitril hidratase dan amidase dari sel Corynebacterium D5.
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Judul: Karakterisasi enzim nitril hidratase dan amidase dalam sel corynebacterium D5
Abstrak: Senyawa nitril seperti asetonitril, akrilonitril merupakan senyawa penting dalam industri yang secara konvensional mempunyai banyak kendala seperti kondisi sintesis yang sulit diatur, adanya produk samping, dan biaya yang tinggi. Industri enzim akan masalah lingkungan menyebabkan teknologi enzim sebagai alternatif guna menggantikan proses kimiawi dalam sintesis senyawa organik dan pengolahan limbah. Salah satu alternatif adalah secara mikrobiologis, yaitu biokonversi yang lebih ekonomis karena kondisi yang lebih mudah diatur serta ramah lingkungan karena dihasilkan produk dengan tingkat kemurnian yang tinggi. Pada penelitian ini ditentukan sejumlah karakter yang meliputi senyawa penginduksi enzim, spesifisitas, kondisi optimum, yaitu pH dan suhu, serta pengaruh ion logam terhadap aktivitas enzim nitril hidratase dan amidase dari sel Corynebacterium D5. Sel Corynebacterium D5 yang ditumbuhkan di empat media, yaitu media mineral + glukosa + NH4Cl, media mineral + asetonitril, media NB + asetonitril, dan media NB diuji aktivitasnya terhadap senyawa nitril dan amida. Aktivitas nitril hidratase hanya ditunjukkan oleh sel Corynebacterium D5 dari media mineral + asetonitril, sehingga enzim nitril hidratase Corynebacterium D5 merupakan enzim yang induktif. Sel Corynebacterium D5 setiap media pertumbuhan menunjukkan aktivitas enzim amidase, sehingga enzim amidase Corynebacterium D5 merupakan enzim konstitutif. Senyawa nitril penginduksi enzim nitril hidratase terbaik adalah asetonitril pada konsentrasi 2% (v/v). Nitril hidratase dan amidase dalam sel Corynebacterium D5 yang telah diinduksi asetonitril 2% (v/v) ditentukan spesifisitasnya. Nitril hidratase dan amidase dapat mendegradasi senyawa nitril atau amida alifatik dengan bobot molekul rendah. Aktivitas nitril hidratase dan amidase ditentukan dengan analisis amonium dengan metode Nessler menggunakan spektrofotometer ultraviolet-tampak. Kondisi optimum enzim nitril hidratase adalah pada pH 6,6, suhu 30°C dengan kofaktor ion logam Fe2+ 5 mM, ion Co²+ 5 mM, dan dihambat oleh ion Ag dan Hg2+. Amidase mempunyai kondisi terbaik pada pH 7,2, suhu 50°C, dengan kofaktor ion logam Fe2+ 1 mM, ion Co²+ 1 mM, dan dihambat oleh ion Ag dan Hg²+.
Keyword: Nitril Hidratase, Amidase, Asetonitril, Akrilonitril, Corynebacterium D5

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