Judul: Sintesis Lacto-N-Biose I Secara Enzimatis Dari Laktosa Dan Glcnac Menggunakan Enzim Lactose Phosphorylase Dan Lacto-N-Biose I Phosphorylase
Abstrak: Lacto-N-biose I (LNB) merupakan salah satu jenis prebiotik yang saat ini telah banyak dikaji khususnya terkait aktivitasnya sebagai bifidus factor. Beberapa penelitian melaporkan bahwa LNB secara signifikan dapat meningkatkan aktivitas mikroflora yang hidup di dalam usus bayi dan balita. Senyawa ini secara alami terdapat di dalam human milk oligosaccharide, akan tetapi seiring dengan perkembangan teknologi, LNB dapat disintesis secara enzimatis. Saat ini, sintesis LNB telah banyak dilakukan, akan tetapi rendemen yang dihasilkan masih rendah dan membutuhkan waktu sintesis yang lama. Oleh karena itu, diperlukan metode yang efisien untuk menghasilkan rendemen tinggi dan dilakukan dengan waktu proses yang singkat. Diketahui bahwa enzim, substrat dan fosfat pada sintesis LNB diyakini dapat mempengaruhi rendemen yang dihasilkan. Pada penelitian ini, dilakukan sintesis LNB secara enzimatis dari laktosa dan GlcNAc dengan menggunakan enzim lactose phosphorylase (LP) dan lacto-N-biose I phosphorylase (LNBP) sebagai katalis. Tujuan penelitian ini yaitu untuk melakukan purifikasi dan karakterisasi enzim LP dan LNBP yang digunakan untuk sintesis LNB. Selain itu diteliti juga pengaruh penambahan enzim, substrat dan fosfat terhadap rendemen LNB yang dihasilkan. Preparasi kultur bakteri dilakukan meliputi transformasi plasmid, pre-kulturisasi dan kulturisasi bakteri. Kemudian dilanjutkan dengan purifikasi enzim dengan menggunakan kromatografi afinitas ion logam imobilisasi seperti: preparasi kolom, pemurnian enzim dan konsentrasi enzim. Setelah itu, dilakukan karakterisasi enzim untuk menentukan aktivitas enzim pada berbagai suhu inkubasi, pH dan konsentrasi substrat. Selanjutnya, dilakukan analisis secara kuantitatif dari sintesis LNB menggunakan high performance liquid chromatography. Hasil penelitian menunjukkan bahwa kondisi optimum katalisis enzim LP terjadi pada suhu 37oC, pH 6 dengan konsentrasi substrat 15 mM, sedangkan kondisi optimum katalisis enzim LNBP terjadi pada suhu 35oC, pH 7 dengan konsentrasi substrat 10 mM. Aktivitas spesifik enzim LP cukup tinggi (18,64 U/mg), sementara enzim LNBP sangat kecil (0,013 U/mg). Peningkatan konsentrasi enzim LP dan fosfat pada sintesis LNB tidak mempengaruhi rendemen yang dihasilkan, sedangkan konsentrasi substrat berpengaruh nyata terhadap rendemen. Sintesis LNB dari laktosa dan GlcNAc menggunakan enzim LP dan LNBP mampu menghasilkan rendemen hingga 75,3%. Metode ini dapat digunakan sebagai alternatif untuk sintesis LNB dari substrat yang lebih murah yang banyak tersedia di alam.
Keyword: prebiotik, lacto-N-biose I, laktosa, GlcNAc, LP, LNBP

Judul: Metabolisme prebiotik oleh kandidat probiotik isolat asi sebagai dasar pengembangan produk sinbiotik
Abstrak: Seven Lactobacillus strains isolated from breast milk were evaluated for their ability to metabolite oligosaccharide known as prebiotics, i. e. inulin, FOS, GOS, FOS:GOS (1:9), and inulin:GOS (1:9). The result shows that all Lactobacillus strains were able to grow in medium with prebiotics as carbon sources. The best growth was observed when GOS or FOS were used as carbon source, while inulin was the worst. The best growth in all oligosaccharides was observed in Lactobacillus R23H, followed by R23, B16, and R14. Further study on R23H and R23 shows that there was no difference in metabolizing oligosaccharides between heterofermenter and homofermenter. GOS was the best prebiotic used by the both lactic acid bacteria as shown by rapid decrease of total sugar. The reducing sugar in medium containing GOS was higher than other oligosaccharides. The decrease of total sugar in medium containing inulin was the slowest among the other prebiotics. This indicate that inulin was the most difficult prebiotic to be metabolized by the selected lactic acid bacteria. When inulin mixed with GOS in the ratio 1:9, the rate of decreasing of total sugar in the medium was similar to the medium with GOS as single carbon source, however it cannot be distinguished if the role of inulin took place after GOS disappear. The rate of sugar metabolism was in accordance with the growth of lactic acid bacteria isolates in medium containing prebiotics. Lactobacillus R23 was used in sinbiotic fermented milk product combine with FOS, inulin, and inulin:GOS (1:9). After fermentation, the result show that remaining sugar in skim milk with additional prebiotics was higher than skim milk without additional prebiotics. Remaining sugar on fermented milk product include the amount of prebiotic that will use as carbon source in colon. Combination of potential probiotic Lactobacillus R23 and mixture of inulin:GOS (1:9) could be used to make sinbiotic fermented milk product.
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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