Judul: Studi awal amobilisasi bakteri Lactococcus lactis subsp lactis menggunakan alginat dengan kitin dan kitosan sebagai kombinasi bahan pembawa (Carrier)
Abstrak: Amobilisasi sel merupakan teknik yang mernbatasi pergerakan sel dalam media hidupnya. Sel teramobil inemiliki kelebihan dibanding sel bebas. Sel terarqobil praktis digunakan, mudah dipisahkan dari aedianya serta dapat digunakan kembali dengan stabilitas produksinya tidak mengalami perubahan yang drastis. Selain itu, sel-seI teranobil akan terpusat sehingga konsentrasi sel per bioreaktor dapat ditingkatkan. Kelebihan-kelebihan yang dimiliki sel amobil dibandingkan sel bebas menjadi daya tarik untuk dikaji lebih dalam. Penelitian ini dilakukan untuk mendapatkan sel amobil dengan persentase pengikatan tertinggi.
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Judul: Imobilisasi sel bakteri amilolitik dengan menggunakan kalsium alginat dan agar
Abstrak: Imobilisasi sel merupakan sel yang secara fisik terbatas atau terlokalisasi dalam suatu area tertentu dan masih mempertahankan aktifitas katalitiknya dan dapat digunakan secara berulang atau kontinyu. Bakteri 4d merupakan bakteri amilolitik, hasil seleksi kuantitatif bakteri ini mempunyai aktivitas tertinggi, yaitu 25,09x104 U/mL. Berdasarkan pengamatan morfologi dan pengujian karakter fisiologi, bakteri 4d diketahui mempunyai ciri-ciri yang menyerupai Bacillus mycoides. Sel B. mycoides dapat diimobilisasi dengan alginat dan agar dengan metode penjeratan. B. mycoides yang diimobilisasi pada matriks alginat 8% mampu menghasilkan amilase dengan aktivitas (13,11 x10 U/mL) yang besarnya kurang lebih dua kali lipat aktivitas amilase yang dihasilkan sel yang diimobilisasi dengan matriks agar 3% (6,85 10 U/mL). Produksi amilase dari B mycoides maksimal pada jam ke-23. Produksi amilase mengalami penurunan pada penggunaan sel imobilisasi yang berulang pada sisrim hacth baik yang menggunakan matriks alginat maupun matriks agar. Penurunan yang nyata terjadi pada fermentasi yang ke dua. Hal ini kemungkinan disebabkan oleh kerusakan butiran akibat pengocokan selama proses fermentasi sehingga terjadi kebocoran sel bakteri yang akan ikut tercuci pada saat pencucian dengan akuades steril setelah fermentasi pertama selesai. Sel terimobilisasi maupun sel bebas menghasilkan amilase pada kisaran pH netral dengan aktivitas tertinggi pada pH media 7,0. Empat macam tepung yang digunakan sebagai sumber karbon untuk memproduksi amilase B mycoides, yaitu beras, ketan, ubi jalar, singkong, dan diperoleh aktifitas imobilisasi sel pada tepung ubi jalar lebih tinggi, yaitu 9,09x10 U/mL.
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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