Judul: Purifikasi parsial B-Galaktosidase Enterobacter cloacae dan penentuan karakternya pada kondisi Teramobil dengan Na-Alginat
Abstrak: Enzim ẞ-galaktosidase (EC 3.2.1.23) merupakan enzim yang dapat menghidrolisis laktosa menjadi glukosa dan galaktosa. Pada penelitian ini, purifikasi parsial B-galaktosidase dilakukan dengan metode pengendapan diikuti dengan dialisis, sementara amobilisasinya dilakukan menggunakan Na-alginat. Tujuan penelitian ini adalah melakukan purifikasi parsial ẞ-galaktosidase dari Enterobacter cloacae dan karakterisasi {pH optimum, suhu optimum, parameter kinetika (Vmaks dan KM)} pada kondisi teramobilisasi dengan Na-alginat. Aktivitas spesifik ẞ- galaktosidase pada ekstrak kasar, pengendapan amonium sulfat 40%, dan dialisis masing-masing sebesar 2.167 U/mg, 5.297 U/mg, dan 12.586 U/mg dengan faktor pemurnian masing-masing sebesar 1,000; 2,445 dan 5,809. Kondisi optimum ẞ- galaktosidase E. cloacae purifikasi parsial yang teramobilisasi adalah pada suhu 40°C dengan aktivitas sebesar 0.012 U/mL dan pada pH 7 dengan aktivitas sebesar 0.009 U/mL, sedangkan parameter kinetikanya adalah Vmaks sebesar 1.273 µmol/menit dan nilai KM sebesar 1.961 mM.
Keyword: Purifikasi, B-Galaktosidase, Amobilisasi

Judul: Purifikasi, amobilisasi, dan karakterisasi β-galaktosidase dari Enterobacter cloacae serta potensinya terhadap susu UHT
Abstrak: Enzymatic hydrolysis of lactose is an important biotechnological process because the hydrolyzed products can be consumed by people with lactose intolerance. The aim of this study was purification, immobilization, and characterization of β-galactosidase from E. cloacae. This research also studied the hydrolysis of lactose in UHT milk. The stages of this research were production and purification β-galactosidase from E. cloacae; characterization of enzyme; optimization of immobilization formula; and hydrolisis of UHT milk. The β- galactosidase from E. cloacae was purified and showed a purification of 30.26- fold, a yield of about 6.18%, and a specific activity of 101.781 U/mg. Free and immobilized enzyme exhibited maximum activity at an optimal pH of 7.0 and an optimum temperature of 40°C. This enzyme was activated by Co2+, Mn2+, and Mg2+; however, was inhibited by Ca2+, Zn2+, Cu2+, and Hg2+. KM for free and immobilized β-galactosidase were 0.434 and 2.068 mM, respectively. Optimal formulation of cell and enzyme immobilization were consist of 10% (w/v) cell with 5% (w/v) sodium alginate and 10% (v/v) purified enzyme with 5% (w/v) sodium alginate, respectively. This researh found that entrapped β-galactosidase was higher in the hydrolysis of lactose present in milk (28.09%) after 6 hours in batch process as compared to entrapped E. cloacae (22.01%) after 18 hours. Free β-galactosidase was higher in the hydrolysis of lactose present in milk (78.20%) after 6 hours as compared to free E. cloacae (55.14%) after 18 hours.
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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