Judul: Kajian citra satelit terra modis untuk mengidentifikasi muatan padatan tersuspensi di perairan Natuna, Laut Cina Selatan
Abstrak: Penelitian dengan topik Kajian Citra Satelit Terra MODIS untuk Mengidentifikasi Muatan Padatan Tersuspensi (MPT) di Perairan NAtuna, Laut Cina Selatan. Dilaksanakan pada bulan Agustus 2005 sampai Desember 2005 di PErairan Natuna yang terletak pada koordinat 2,89° LU - 5,98° LU dan 105,29° BT - 109,07° BT.
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Judul: Kondisi  Lingkungan Perairan Natuna Berdasarkan Data Citra Modis dan Indeks Kualitas Lingkungan
Abstrak: Kondisi lingkungan Perairan Natuna diteliti berdasarkan data satelit dengan menggunakan citra MODIS dan data in situ yang diambil pada tanggal 22-30 Januari 2005. Berdasarkan citra MODIS kandungan klorofil-a berkisar antara 0,10-1,00 mg/m3; suhu permukaan laut berkisar antara 27,00-28,00 derajat Celcius; kandungan padatan tersuspensi berkisar pada 0,01-0,03 mg/l; dan kandungan coloreddissolved organic matter (CDOM) berkisar antara 0,02-0,05 m-1. Nilai-nilai ini jauh berbeda dengan hasil pengukuran di lapangan (in situ), dimana kandungan klorofil-a berkisar antara 0,1161-1,2055 mg/m3; suhu permukaan laut berkisar antara 29,0-30,01 derajat Celcius; dan kandungan padatan tersuspensi berkisar pada 45-75 mg/l. Perbedaan ini disebabkan oleh belim adanya algoritma penduga parameter kualitas perairan yang sesuai dengan kondisi perairan di Indonesia, khususnya Perairan Natuna. Perairan Natuna berdasarkan beberapa parameter kualitas perairan hasil pendugaan citra MODIS, yaitu klorofil-a, suhu permukaan laut, total padatan tersuspensi dan colored dissolved organis matter (CDOM), memiliki kondisi yang cukup baik dan tidak terjadi pencemaran minyak maupun bahan pencemar lainnya. Kesimpulan ini didapatkan setelah dilakukan perbandingan dengan baku mutu lingkungan perairan Keputusan Menteri Negara Lingkungan Hidup no. 51/MENLH/2004
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Judul: Heterologous Expression Of Endo-Β-Xylanase From Bacillus Pumilus Strain Bcrs-01 In Escherichia Coli.
Abstrak: Xylanases are glycoside hydrolase family 11 which depolymerise xylan in the plant cell wall, the most excessive form of hemicellulose. Endo-β-xylanases (EC 3.2.1.8) are most important to breakdown β-1,4-glicoside bond of xylan to produce disaccaride xyloolygosaccaride (XOs) and xylose (monomer). Bovine rumen fluids have potential to obtain endo-β-xylanase produced of bacteria. The objectives of this study were to obtain xylanase producing bacteria and to express xynA gene encoding endo-β-xylanase from bacterium in Escherichia coli. Twenty nine isolate bacteria have been succesfully isolated from bovine rumen fluid in agar medium containing birchwood xylan. Isolate BCRS-01 bacterium was previously screened for the high production of xylanase. Based on 16S rRNA gene sequence analysis, BCRS-01 showed high similarity (99%) to Bacillus pumilus (accession number NR043241). The crude xylanase had optimal activity at 55oC, pH 7.0. Furthermore, the crude xylanase exhibited broad pH stability from 4.0 to 10.0 and remained more than 60% and 40% of its activity after incubation at pH 4.0 until 10.0, respectively for 60 min. It also showed a stability at temperature 25-50oC since it retained 80% and 50% of its activity when incubated at 50oC or 30 and 60 min, respectively. The xylanase activity was strongly inhibited by Ca2+ and Cu2+ at concentration 10 mM, and as little as 1 mM for Mn2+. Therefore, this xylanase has potentially used as additive feeds in animal feed industry. The DNA sequence xynA gene encoded endo-β-xylanase was amplified and cloned into the expression vector pET-15by under the control of T7 promoter. The recombinant protein had succesfully expressed in Escherichia coli BL21 (DE3) pLysS. A protein recombinant of approximately, 26.7 kDa was observed on the SDS-PAGE analysis. Crude extract of recombinant endo-β-xylanase demonstrated activity of enzyme at 56 U mL-1 using birchwood xylan as a substrate at 55oC for 10 min.
Keyword: Bacillus pumilus, bovine rumen fluid, endo-β-xylanase, heterologous expression.