Judul: N2 fixation and methane oxidation activity of mixed of culture of Azotobacter sp., Azospirillum sp., and Methanotrophic Bacteria
Abstrak: Metanotrophs bacteria are methane oxidizing bacteria. Methanotrophic bacteria especially type II and type X were also able to fix nitrogen using nitrogenase enzyme. This reasearch was conducted to determine activity of methane oxidation and nitrogen fixation of four isolates of methanotropic bacteria i.e. BGM 1, BGM 5, BGM 9, and SKM 14 which were combined with nitrogen-fixing bacteria (Azotobacter sp. and Azospirillum sp.). Six combinations were cultured and then inoculated into nitrogen free NMS medium. Activity of methane oxidation and nitrogen fixation activity was analysed. The highest methane oxidation activity was found in the mixed culture of BGM 9, BGM 5, Azotobacter sp., and Azospirillum sp. isolates. The activity was 184.5 x 10-8 ìM/cell /day. The highest accumulation of ammonium was found in the mixed culture of BGM 5, BGM 9, and Azotobacter sp. isolates. The concentration of accumulated ammonium was 4.075 ìM. Methane oxidation activity and ammonium accumulation of methanotrophic bacteria showed higher result when they were combined with nitrogen fixing bacteria.
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Judul: Aktivitas fiksasi nitrogen dan oksidasi metan kultur campuran bakteri metanotrof pada lumpur sawah
Abstrak: Metanotroph bacteria are methane oxidizing bacteria. Besides, type II and type X of methanotrophic bacteria were also able to fix nitrogen using nitrogenase enzyme. This reasearch was conducted to test the activity of nitrogen fixation and methane oxidation of five isolates of methanotropic bacteria i.e. BGM 1, BGM 3, BGM 5, BGM 9, and SKM 14 which combined with one another. Seven combinations (SKM 14/BGM 1; SKM 14/BGM 3; SKM 14/BGM 5; SKM 14/BGM 9; BGM 9/BGM 1; BGM 9/BGM 3; BGM 9/BGM 5) were cultured and inoculated into NMS medium mixed with slurry of mud, then the activity of methane oxidation, nitrogen fixation and nitrogenase enzyme activity was tested. The highest accumulation of ammonium in the mud sterile treatment (35.489 μM) was higher than that of in non-sterile mud treatment (26.617 μM). Formulation 6 (BGM 9/BGM 3) in sterile mud treatment and formulation 4 (SKM 14/BGM 9) in non-sterile mud treatment has the highest nitrogenase enzyme activity, it was 5,16 mmol/h/ml culture and 75,85 mmol/h/ml culture respectively. Formulation 1 (SKM 14/BGM 1) and formulation 2 (SKM 14/BGM3) had the higest activity of methane oxidation in sterile and non sterile mud treatment i.e. 17428 and 16759 ppm /ml culture /day respectively.
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Judul: Kerugian ekonomi akibat serangan rayap pada bangunan perumahan di dua wilayah DKI Jakarta (Kotamadya Jakarta Barat dan Jakarta Timur)
Abstrak: Perusakan bangunan rumah oleh rayap dipengaruhi oleh kondisi lingkungan tempat hidupnya. Peranannya bervariasi untuk masing-masing tempat. Daerah-daerah tertentu misalnya dekat sungai, banyak pepohonan, kelembaban, dan curah hujan yang cukup cenderung tinggi tingkat serangan rayapnya. Daerah Kecamatan Keramat Jati dan Ciracas merupakan daerah yang kerugian ekonominya cukup tinggi, yaitu sebesar Rp. 5.496.490 dan Rp. 4.193.353, disusul daerah Palmerah, Kembangan, Kebun Jeruk dengan kerugian sebesar Rp. 4.895.392, Rp. 4.735.653, dan Rp. 4.732.646. Kerugian yang terkecil terdapat pada daerah Kecamatan Cipayung yaitu sebesar Rp. 4.255.909. Penelitian juga mengungkapkan bahwa adanya hubungan antara umur bangunan rumah dengan tingkat serangan rayap dan besarnya kerugian ekonomi akibat serangan rayap. Tingkat serangan rayap dan kerugian ekonomi berbanding lurus dengan kelas umur bangunan rumah, semakin besar umur bangunan tingkat serangan rayap dan kerugian ekonomi akan semakin besar. Daerah Kecamatan Keramat Jati, Ciracas dan Palmerah perlu mendapat perhatian yang serius, mengingat daerah tersebut mempunyai kerugian ekonomi yang cukup tinggi akibat serangan rayap. Diharapkan para pengambil kebijaksanaan dalam merancang desain bangunan perumahan dapat memperhatikan proteksi bangunan terhadap bahaya rayap.
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