Judul: Pendugaan Kadar NO2 dengan Metode Ordinary Kriging dan Cokriging (Studi Kasus : Pencemaran Udara di Kota Bogor).
Abstrak: Pencemaran udara merupakan salah satu masalah yang dihadapi berbagai kota. Salah satu gas pencemar udara yang dianggap berbahaya yaitu NO2(Nitrogen Dioksida). Metode ordinary kriging dan cokriging digunakan untuk menduga kadar NO2 dengan adanya pengaruh spasial. Arah mata angin atau sudut anisotropik yang berbeda yaitu dari arah utara (0o), timur laut (45o), timur (90o) dan tenggara (135o) dapat meningkatkan presisi pendugaan kadar NO2. Hasil interpolasi NO2 lalu dibandingkan antara metode ordinary kriging dan cokriging pada empat sudut anisotropik. Metode ordinary kriging dan cokriging pada empat sudut anisotropik dapat menduga kadar NO2 dengan cukup baik. Perbandingan hasil interpolasi NO2 berdasarkan nilai akar kuadrat tengah galat(RMSE) menunjukkan bahwa metode cokriging khususnya pada sudut anisotropik 1350 lebih baik daripada metode ordinary kriging. Kata kunci : anisotropik, cokriging, ordinary kriging
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Judul: Pola Distribusi Spasial dan Temporal Polutan NO2di Wilayah Kabupaten Bogor dan Sekitarnya Menggunakan Data Ozone Monitoring Instrument
Abstrak: Kota dan Kabupaten Bogor saat ini merupakan daerah yang sedang melakukan pengembangan infrastruktur pada segala bidang. Namun pengembangan tersebut tidak didukung dengan usaha penanganan masalah lingkungan. Salah satu masalah lingkungan adalah polusi udara. Penelitianini bertujuan untuk mengetahui dan mendeskripsikan tingkat serta pola distribusi polutan NO2 di Kabupaten Bogor dan sekitarnya menggunakan data hasil remote sensingsatelit AURA (OMI) dansoftwareGiovanni. Penelitian dilakukan menggunakan data 5 tahun (2006–2010) didapatkan bahwa tingkat kandungan NO2 tertinggi di atmosfer Kabupaten Bogor terjadi pada bulan Juli 2008 sebesar 10 × 1015 molec/cm2, sedangkan terendah terjadi pada bulan Januari 2006 sebesar2 × 1015molec/cm2. Berdasarkan data curah hujan rata-rata dari 7 stasiun yang tersebar di Kabupaten Bogor, dibuat rata-rata musiman menjadi empat, yaitu musim hujan pada DJF (Desember–Januari–Februari); musim peralihan MAM (Maret–April–Mei); musin kemarau JJA (Juni–Juli–Agustus); dan musim peralihan SON (September–Oktober–November). Pola sebaran NO2 pada bulan DJF dan MAM menghasilkan nilai total kolom NO2yang bernilai rendah dibandingkan dengan bulan JJA dan SON yang menunjukkan nilai total kolom NO2 yang cenderung tinggi.
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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