Judul: Production and Immobilization of Pectinase from Bacillus sp. 2P11 Using Alginate Beads
Abstrak: Enzymes are biocatalysts with high catalytic power that have the potential to be used in the industrial field. Pectinase is an enzyme that degrades plant cell walls and is commonly used in the food industry to accelerate the extraction of fruit juices. Microbes are a source of enzymes that are often used because they grow on various media and can easily be increased by adjusting the growth conditions. Immobilization is the stage of developing a sustainable bioprocess by reusing enzymes bound to a matrix. Therefore, this study aimed to immobilize the pectinase enzyme and the efficiency of repeated use of the immobilized pectinase. This research begins with the rejuvenation of Bacillus sp. 2P11, which has been isolated from previous studies. The cocoa husk contains pectin, which can be used as a substrate to produce pectinase. Pectinase production was carried out by growing Bacillus sp. 2P11 on liquid production media with a cocoa liquid substrate with variations (1-15%) was tested for enzyme activity. Crude extract enzyme activity was obtained by optimizing microbial growth on the media by making an enzyme production curve. The enzyme production curve makes with an incubation time of 96 hours and observations every 12 hours. Enzyme activity was measured using Dinitrosalicylic Acid (DNS) reagent with a standard solution of galacturonic acid. Precipitation was carried out with ammonium sulfate salt and then dialyzed. The enzyme was precipitated gradually from 0% to the ammonium sulfate saturation level of 80%. Dialysis was carried out by inserting a cellophane tube containing the enzyme into a 0,05 M pH 5 acetate buffer. The purified pectinase was then immobilized by trapping using sodium alginate and CaCl2. Immobilized pectinase stored for 14 days was measured for its enzyme activity repeatedly. The activity of the crude extract of the pectinase enzyme obtained was 0,41 U/mL. Precipitation with ammonium sulfate and dialysis increased pectinase activity by 0,45 U/mL and 0,58 U/mL, respectively. Enzymes can be used repeatedly with enzyme immobilization. In this study, the immobilization of the enzyme entrapment method with sodium alginate and CaCl2 was designed with the response surface method. The optimum concentration of sodium alginate was 0,5%, and CaCl2 0,3 M, with the percentage of an immobilized enzyme was 40,7%, and pectinase activity was 0,23 U/mL. Stability and repeated use of immobilized pectinase can be done up to 5 times., Enzim adalah biokatalis dengan daya katalik tinggi yang memiliki potensi untuk digunakan pada bidang industri. Pektinase merupakan enzim pendegradasi dinding sel tanaman yang umum digunakan untuk industri pangan seperti mempercepat ekstraksi sari buah. Mikroba merupakan sumber penghasil enzim yang sering digunakan karena tumbuh pada berbagai media dan mudah ditingkatkan hasilnya dengan mengatur kondisi pertumbuhan. Imobilisasi merupakan tahapan pengembangan bioproses berkelanjutan dengan menggunakan kembali enzim yang terikat pada suatu matriks. Oleh karena itu, tujuan penelitian ini yaitu melakukan imobilisasi enzim pektinase dan mengukur efisiensi penggunaan berulang pektinase imobil tersebut. Penelitian ini diawali dengan peremajaan isolat Bacillus sp. 2P11 yang telah diisolasi dari penelitian terdahulu. Kulit kakao mengandung pektin sehingga dapat digunakan sebagai substrat untuk menghasilkan pektinase. Produksi pektinase dilakukan dengan menumbuhkan Bacillus sp. 2P11 pada media
Keyword: Alginate beads, Bacillus sp. 2P11, cacao, pectinase, immobilization

Judul: Isolasi Mikroba Penghasil Pektinase dan Optimalisasi Produksinya pada Penjernihan Sari Buah Apel (Malus domestica).
Abstrak: Pektinase merupakan kelompok enzim yang mampu menghidrolisis polimer pektin, yaitu polisakarida yang banyak ditemukan dalam dinding sel tumbuhan, terutama pada bagian lamela tengah. Kandungan polisakarida seperti pektin tersebut menyebabkan terbentuknya kekeruhan dalam pengolahan sari buah. Saat ini pektinase memegang peranan penting dalam industri minuman karena kemampuannya meningkatkan kejernihan dan mengurangi kekentalan sari buah. Pektinase secara alami dapat ditemukan pada hewan, tumbuhan dan mikroba. Saat ini mikroba menjadi sumber utama dalam menghasilkan pektinase karena sifatnya yang mudah ditumbuhkan, proses pemanenan enzim lebih mudah dan hasil akhir yang dapat ditingkatkan melalui rekayasa genetika. Berdasarkan hal tersebut, maka perlu dilakukan eksplorasi mengenai mikroba pektinolitik potensial yang dapat diaplikasikan dalam bidang industri. Penelitian ini diawali dengan tahap isolasi mikroba pektinolitik dari sampel fermentasi kakao dan limbah kulit kakao yang berasal dari Perkebunan Kakao, Balitri Sukabumi, Jawa Barat. Pemilihan sampel fermentasi kakao didasari oleh berbagai penelitian yang melaporkan bahwa adanya peranan mikroba pektinolitik yang bekerja mendegradasi daging buah kakao yang mengandung pektin sehingga mampu mempercepat pengelupasannya dari biji kakao. Isolat-isolat yang diperoleh selanjutnya diseleksi berdasarkan pembentukan zona bening dengan tujuan mendapatkan isolat unggul pektinolitik. Optimasi produksi pektinase dilakukan berdasarkan sumber karbon dan nitrogen. Pektinase yang dihasilkan selanjutnya diuji aktivitasnya terhadap variasi pH dan suhu untuk mengetahui karakternya. Tahap akhir penelitian ini adalah menguji kemampuan pektinase dalam aplikasi penjernihan sari buah apel. Isolat-isolat hasil isolasi di tahap awal diseleksi dengan mengamati diameter zona bening yang terbentuk. Berdasarkan data diameter tersebut diperoleh berbagai nilai indeks pektinolitik dan isolat 2P11 memiliki nilai indeks paling besar yaitu, 4.13. Hasil identifikasi 16S RNA menyatakan isolat 2P11 merupakan bakteri jenis Bacillus sp.. Sitrus pektin dan pepton merupakan komponen yang optimal untuk produksi enzim pektinase. Hasil karakterisasi enzim menyatakan bahwa enzim pektinase yang dihasilkan oleh isolat 2P11 memiliki aktivitas optimum pada pH 5, suhu 40 °C dan aktivitas tertingginya diperoleh pada satu jam pertama penyimpanan. Kemampuan pektinase dalam menghidrolisis pektin diuji pada proses penjernihan sari buah apel. Pektinase dengan berbagai nilai aktivitas (0.118, 0.329, 0.509, 0.999 U/mL) ditambahkan pada sari buah apel selanjutnya diukur pH, kejernihan dan nilai viskositasnya. Hasil menunjukkan bahwa pektinase dengan aktivitas 0.999 U/mL mampu menurunkan nilai pH dan meningkatkan kejernihan sari buah apel dibandingkan sari buah apel tanpa pemberian enzim. Berdasarkan hasil tersebut diketahui bahwa pektinase dapat diaplikasikan untuk meningkatkan kualitas sari buah apel.
Keyword: apel, Bacillus, enzim, karakterisasi, pektinase, penjernihan, sari buah

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