Judul: Analisis curah hujan dengan fungsi ortogolal empirik
Abstrak: Pola iklim yang paling dominan ditentukan oleh besar- nya kontribusi salah satu faktor penentunya. Umumnya pola curah hujan di Indonesia dipengaruhi oleh sistem sirkulasi udara Muson yang menyebabkan adanya periode basah dan periode kering dalam setahun. Perbedaan pola dari satu tempat ke tempat lain dipengaruhi oleh sistem lokal seper- ti lintang, geografi dan topografi tempat. Penelitian ini bertujuan untuk mengidentifikasi pola ruang dan pola periodik curah hujan bulanan di DAS Cili- wung. Penentuan pola dilakukan dengan analisis fungsi ortogonal empirik. Pola curah hujan di wilayah DAS Ciliwung didominasi pola curah hujan musiman yang disebabkan sirkulasi Muson. Total keragaman yang diterangkan sebesar 54% dan periodisitas 12 bulan (setahun). Curah hujan selama per- alihan musim diduga disebabkan oleh pengaruh sistem angin- angin lokal terutama angin laut, dan proses konveksi massa uap air dari permukaan yang menyumbang keragaman 10% dan periodisitas 6 bulan (semi-tahunan), sedangkan curah hujan orografik menyumbang 4%. Selama peralihan musim daerah Bogor (DAS bagian tengah) merupakan wilayah yang menyumbang keragaman paling ...
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Judul: Analisis parameter hidrometeorologi di daerah aliran sungai Ciliwung
Abstrak: Data iklim dan hidrologi merupakan salah satu aspek data fisik yang merupakan data dasar dalam mempersiapkan pengembangan dan pengelolaan daerah aliran sungai (DAS). Data iklim dan hidrologi ini tidak ada artinya jika tidak dianalisis. Salah satu cara untuk menganalisisnya adalah dengan analisis statistik, karena dengan analisis statis- tik dari suatu deretan data dapat memberikan gambaran yang jelas tentang suatu keadaan menurut ruang dan waktu. Tujuan analisis ini untuk mengetahui sifat sebaran data curah hujan bulanan, sebaran curah hujan bulanan se- panjang tahun pada berbagai peluang kejadian dan untuk me- ngetahui hubungan antar unsur iklim di sepanjang daerah aliran Sungai Ciliwung. Analisis curah hujan bulanan dihitung dengan nilai rata-rata, simpangan baku, koefisien keragaman, korelasi diri, dan analisis frekuensi dari data pengamatan tahun 1951 1986 di 31 stasiun penakar hujan di sepanjang DAS. Hubungan antar unsur iklim dilihat dari nilai koefisien korelasi dan analisis regresi linier (data diperoleh dari 3 lokasi, Jakarta, Bogor dan Citeko dengan periode penga- matan tahun 1984 1986). ...
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Judul: Extracellular Expression of thermostable Geobacillus stearothermophilus T1.2RQ Lipase for Biodiesel Production
Abstrak: The extracellular expression of enzymes in an excellent secretion host such as Bacillus subtilis is a useful strategy for making enzymes of industrial significance more affordable by lowering the cost of its downstream processing. Lipases are a category of hydrolases that catalyze the hydrolysis of triglycerides to glycerol and free fatty acids. Also, lipases catalyze the hydrolysis and transesterification of other esters as well as the synthesis of esters. They can perform very specific biotransformation reactions and are widely used in food, organic synthesis, detergents, cosmetic, and pharmaceutical industries. Geobacillus stearothermophilus T1.2RQ lipase is an industrially-desired thermostable lipolytic enzyme with an excellent hydrolytic and transesterification activity. This study aimed to express T1.2RQ lipase, in B. subtilis WB800 and ensure its secretion into the extracellular medium. Three signal peptides (AmyQ, Epr, LipA) and two promoters (Pgrac01 and Pgrac100) were used in the secretory-expression of T1.2RQ lipase, based on five constructed expression vectors constructed by restriction cloning and PCR mutagenesis. Sangers sequencing was used to verify constructs to ensure they are in the correct reading frame. Recombinants vectors, pHT43 (plasmid control), pHT43-T1.2RQ, pHT43- T1.2RQ_AmyQ, pHT43-T1.2RQ_Epr, and pHT43-T1.2RQ_LipA, were transformed by electroporation into Bacillus subtilis WB800. The electroporation was successful with the optimum condition of 2500V, 200 ohms, 25µF, and 5milliseconds. Recombinant B. subtilis pHT43 (negative control) and pHT43-T1.2RQlip + signal peptides were streaked on the lipidic agar, LA+TBN. All four recombinants, including the negative control (B. subtilis WB800-pHT43), produced clear zones on the TBN agar plate after overnight incubation (fig 2), indicating the presence of a lipolytic enzyme in all of the recombinant B. subtilis cells. pHT43-T1.2RQlip + signal peptides (AmyQ, Epr, and LipA) have clear zones with significantly higher diameters than B. subtilis WB800-pHT43 (negative control). This phenomenon suggests that the recombinant thermostable lipase T1.2RQ introduced into these cells was successfully expressed, thereby increasing the lipolytic capability of its host cells T1.2RQ lipase was expressed in 50ml terrific broth medium (TB) and the expression induced with 1mM IPTG. Lipase activity assay using p-nitrophenyl esters showed that all three signal peptides directed the secretion of T1.2RQ lipase into the extracellular medium. Signal peptide, LipA, resulted in the highest extracellular activity of 5.6 U/mL, which corresponds to a 6-fold increase over the parent B. subtilis WB800 strain. Meanwhile, signal peptides, AmyQ and Epr produced 4.2 U/mL and 3.4 U/mL activity respectively. SDS-Zymogram analysis confirmed that T1.2RQ lipase was correctly processed and secreted in its original size of 44 kDa. An attempt to further increase lipase expression level by promoter optimization showed that, contrary to expectation, promoter Pgrac100 exhibited similar expression levels as the original Pgrac01. Nevertheless, the demonstration of the successful secretion of T1.2RQ lipase in this work confirms the latter as a promising approach for the industrial production of the enzyme
Keyword: Bacillus subtilis, Expression, Extracellular, Heterologous, Lipase, Thermostable