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"Telah dilakukan penelitian untuk mengetahui laju fiksasi nitrogen strain-strain Nostoc [Vaucher 1803] Bornet et Flahault 1886. Penelitian menggunakan 8 strain Nostoc koleksi Laboratorium Taksonomi Tumbuhan, Departemen Biologi, FMIPA UI. Penelitian menggunakan metode Acetylene Reduction Assay (ARA) dengan 2 ulangan untuk setiap strain Nostoc. Pengujian dilakukan pada strain yang telah berumur 21 hari. Biomassa berat basah strain Nostoc yang digunakan adalah 0,1 gram. Masing-masing strain diinkubasi selama 30, 60, dan 90 menit dengan menambahkan 1 ml gas asetilen.Hasil penelitian menunjukkan data yang bervariasi untuk masing-masing strain Nostoc pada masing-masing waktu inkubasi. Sebanyak 6 strain Nostoc menunjukkan nilai laju fiksasi nitrogen tertinggi pada waktu inkubasi 30 menit. Sebanyak 2 strain Nostoc menunjukkan nilai laju fiksasi nitrogen tertinggi pada waktu inkubasi 60 menit. Strain Nostoc BTM6-02 menunjukkan nilai laju fiksasi nitrogen yang paling tinggi yaitu 3892,5 μmol (dicapai pada inkubasi 60 menit). Strain Nostoc CPG24 menunjukkan nilai laju fiksasi nitrogen yang paling rendah, yaitu 292,44 μmol (dicapai pada inkubasi 90 menit).

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The research of nitrogen fixation rate of Nostoc [Vaucher 1803] Bornet et Flahault 1886 have been done. Eight strains of Nostoc from Plant Taxonomy Culture Collection, Department of Biology, Faculty of Mathematics & Natural Sciences, University of Indonesia, were used. The measurement of nitrogen fixation used Acetylene Reduction Assay (ARA) method with 2 samples for each strain. Experiments were conducted using strains at 21st day age. Wet weight of each strain was 0.1 gram. Then, each Nostoc strain was incubated with addition of 1 ml acetylene for 30, 60, and 90 minutes.

The experiment result showed a different value for each Nostoc strain in every incubation times. Six Nostoc strains showed the highest value of nitrogen fixation after incubated for 30 minutes. Two Nostoc strains showed the highest value of nitrogen fixation after incubated for 60 minutes. Nitrogen fixation rate of BTM6-02 reached the highest value of 3892.5 μmol after incubated for 60 minutes. Nitrogen fixation rate of CPG24 was the lowest ones (292.44 μmol) after incubated for 90 minutes."

"Penelitian tentang metode freezing (-4° C) dengan menggunakan freezer lemari pendingin untuk preservasi 13 strain Nostoc [Vaucher 1803] Bornet et Flahault 1886 telah dilakukan. Penelitian bertujuan untuk mengetahui kemampuan tumbuh dan respon tumbuh strain Nostoc setelah dipreservasi. Strain Nostoc yang diujikan berumur 15 hari dalam medium BG11 bebas unsur nitrogen (pH 7,2). Preservasi koloni Nostoc menggunakan DMSO 5% selama 1 dan 7 hari. Koloni Nostoc tanpa penambahan DMSO 5% digunakan sebagai kontrol. Masing-masing perlakuan dan kontrol dilakukan dalam dua kali ulangan.Hasil penelitian menunjukkan sebanyak 11 dari 13 strain (84,62%) dapat bertahan dan berhasil tumbuh setelah preservasi. Sebelas strain Nostoc tersebut menunjukkan respon tumbuh yang berbeda-beda. Metode freezing (-4° C) menggunakan freezer lemari pendingin dapat digunakan sebagai metode preservasi strain Nostoc yang sederhana dan mudah.

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The use of freezing method (-4° C) by using freezer refrigerator for preservation thirteen Nostoc [Vaucher 1803] Bornet et Flahault 1886 strains had been studied. The purpose of this study was to assess strains ability to grow and grow response after being preserved. Nostoc strains cultured in BG11 N free agar (pH 7,2) for 15 days were used. The preservation used 5% DMSO for 1 and 7 days. Nostoc colonies without presence of 5% DMSO were used as a control. Each test was carried out in duplicate.

The results showed that 11 of 13 strains (84,62%) were able to survive and grow after treatment. 11 Nostoc strains showed different grow response. Freezing method (-4° C) by using freezer refrigerator can be used as a simple and inexpensive preservation method for Nostoc strains."

"Penelitian bertujuan untuk mengetahui pengaruh metode freezing (-4oC) terhadap kadar klorofil dan protein pada 13 strain Nostoc koleksi Laboratorium Taksonomi Tumbuhan, Departemen Biologi FMIPA UI. Protektan DMSO 5% digunakan sebagai medium preservasi pada perlakuan, dan pada kontrol digunakan medium cair BG 11 N-free. Pengaruh metode freezing diketahui dengan membandingkan kadar klorofil dan protein pada sebelum dan sesudah preservasi (hari ke-0, hari ke-1, dan hari ke-7).Hasil penelitian menunjukkan bahwa kadar klorofil dan protein pada kelompok perlakuan lebih besar daripada kontrol. Tiga dari tiga belas strain (23,08 %) mengalami penurunan kadar klorofil sebesar 7,32% -- 47,02% setelah preservasi, sedangkan lima dari tiga belas strain (38,46%) mengalami penurunan kadar protein sebesar 7,69%--37,5% setelah freezing.

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The purpose of this study was to assess the effect of freezing method (-4oC) on chlorophyll and protein content of 13 Nostoc strains Culture Collection of Plant Taxonomy Laboratory FMIPA UI. The protectan used DMSO 5%, and liquid BG 11 N-free medium was used as control. The effect of freezing was evaluated by comparing the content of chlorophyll and protein of Nostoc before and after preservation (day-0, day-1, and day-7).

The result showed that the control had lower chlorophyll and protein content than the treatment. The chlorophyll content of three strains (23,08%) decreased about 7,32% -- 47,02% after freezing treatment, while the protein content of five strains (38,46%) decreased about7,69% -- 37,5%."

"Permasalahan yang menghalangi keberhasilan sintesis ACNT di DTK UI terletak pada sumber karbon yang kurang reaktif serta deposit karbon yang lebih banyak pada dinding reaktor dibandingkan substrat yang diinginkan. Pengujian kali ini akan mempelajari pengaruh dari substrat yang digunakan, yaitu substrat wire gauze SS304, bola SiO2, dan kuarsa. Sebagai sumber karbon, asetilen digunakan karena kemampuannya yang terbukti mampu menghasilkan ACNT dalam setiap percobaan pertumbuhan. Metode yang digunakan adalah floating catalyst chemical vapor deposition dengan katalis berupa ferrocene. Dalam penelitian ini, pengaruh penggunaan hidrogen juga diperhatikan untuk melihat hasil pertumbuhan dengan setiap substrat yang digunakan. Hasil pengujian menunjukkan bahwa setiap substrat yang digunakan mampu membentuk CNT, namun belum mencapai bentuk ACNT. Bentuk lainnya yang terbentuk adalah carbon nanofoam dan carbon helical. Substrat wire gauze SS304 memiliki yield yang paling tinggi, yaitu sebesar 0,6875, namun hanya sedikit CNT yang tumbuh. Pada substrat bola silika, meskipun yield yang dihasilkan rendah atau hampir tidak ada deposit pada substrat tersebut, namun dapat memberikan hasil CNT yang baik. Substrat kuarsa memberikan persentase yang paling tinggi dengan nilai 0,1073% dengan jangkauan diameter 35-99 nm, lebih sempit daripada bola silika dengan jangkauan diameter 35-123 nm. Penggunaan hidrogen memberikan efek terhadap peningkatan yield dan mengecilkan diameter CNT yang dihasilkan.

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The problems that hinder the success of the ACNT synthesis in DTK UI lies in the carbon source which is less reactive and there’s more carbon deposits on the walls of the reactor than the desired substrate. This testing will study the effect of substrate used, those are the SS 304 wire gauze, SiO2 spheres, and quartz cylinder substrate. As the carbon source, acetylene is used because of its proven ability of producing ACNT growth in each experiment. The method used is floating catalyst chemical vapor deposition with ferrocene as the catalyst. In this study, the effect using hydrogen also be considered to see with each substrate used.

The results show that each substrate used can form CNT, but has not reached ACNT form. Other shapes of CNT that also found are carbon nanofoam and helical carbon. SS304 wire gauze substrate has the highest yield, that is equal to 0.6875, but only a few CNTs are grown. On a substrate of silica spheres, although the resulting yield is low or almost no deposit on the substrate, but it can give good results CNT. Quartz substrates provide the highest percentage with the value of 0.1073% and diameter range in 35-99 nm, narrower than the silica spheres with a diameter range in 35-123 nm. The use of hydrogen give effect to increase yields and reduce the diameter of the CNT generated."

"Telah dilakukan penelitian mengenai potensi bakteri basil indigenous sebagai plant growth promoting bacteria (PGPB). Isolat G7, G10 dan G18 yang berpotensi dalam meningkatkan pertumbuhan tanaman diisolasi dari saluran pencernaan larva lalat tentara hitam, sedangkan isolat B. siamensis LDR dengan potensi sebagai agen biokontrol diisolasi dari cocopeat. Penelitian ini dilakukan untuk untuk mengetahui karakterisasi pertumbuhan dari isolat G7, G10 dan G18, meliputi pH medium (5, 6, 7, 8, 9) dan suhu inkubasi (30, 40, 50 oC). Uji antagonisme dilakukan antara isolat G7, G10 dan G18 dengan B. siamensis LDR guna melihat kemungkinan isolat-isolat tersebut untuk disatukan dalam satu konsorsium. Uji kemampuan memfiksasi nitrogen dan memproduksi siderofor dilakukan pada isolat G7, G10, G18 dan B. siamensis LDR.  Hasil menunjukkan bahwa isolat G7, G10 dan G18 dapat tumbuh pada pH 5—9 dengan pertumbuhan optimum pada kisaran pH 7—9. Suhu optimum bagi ketiga isolat diketahui pada 40 oC. Terdapat hubungan antagonisme isolat G7, G10 dan G18 terhadap B. siamensis LDR sehingga isolat-isolat tersebut tidak dapat disatukan dalam satu konsorsium. Kemampuan memfiksasi nitrogen ditunjukkan oleh isolat G7 dan G10. Kemampuan memproduksi siderofor dimiliki oleh semua isolat, yaitu G7, G10, G18 dan juga B. siamensis LDR. Isolat G7 dan G10 yang mampu memfiksasi nitrogen serta memproduksi siderofor merupakan isolat yang lebih unggul karena memiliki karakteristik PGPB yang lebih lengkap.

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Research has been carried out on the potential of several indigenous bacili bacteria as plant growth promoting bacteria (PGPB). Isolates G7, G10 and G18 with potential to increase plant growth were isolated from the digestive tract of black soldier fly larvae, while B. siamensis LDR with potential as a biocontrol agent was isolated from cocopeat. This research was conducted to determine the growth characteristics of isolates G7, G10 and G18, including medium pH (5, 6, 7, 8, 9) and incubation temperature (30, 40, 50 oC). Antagonism test was carried out between isolates G7, G10 and G18 against B. siamensis LDR to see the possibility of these isolates to be combined in one consortium. The ability to fix nitrogen and produce siderophores were carried out on isolates G7, G10, G18 and B. siamensis LDR. The results showed that isolates G7, G10 and G18 could grow at pH 5—9 with optimal growth in the range of pH 7—9. The optimum temperature for the three isolates was at 40 oC. There was an antagonistic relationship between isolates G7, G10 and G18 towards B. siamensis LDR so these isolates could not be combined into one consortium. The ability to fix nitrogen was shown by isolates G7 and G10. The ability to produce siderophores was shown by all isolates, namely G7, G10, G18 and also B. siamensis LDR. Isolates G7 and G10 which are able to fix nitrogen and produce siderophores, were the best isolates because they have more complete characteristics as PGPB."

"ABSTRAKPreservasi koleksi kultur Nostoc dilakukan mengingat Nostoc merupakan salah satu mikroalga tanah yang penting dan berguna. Metode preservasi yang umum digunakan untuk Nostoc adalah dengan subkultur berkala dan freezing. Delapan strain Nostoc yang digunakan dalam preservasi dengan metode freezing pada suhu (-80oC) adalah CPG8, CPG24, BAD5, GIA13a, GIA12-03, TAB7d, BTM6-01 dan TAK23. Penambahan protektan intraseluler DMSO 5% dilakukan untuk mengurangi efek dari proses freezing (cold stress) pada Nostoc. Sebagai pembanding, delapan strain tersebut juga dipreservasi tanpa menggunakan protektan (kontrol negatif) dalam medium BG 11 bebas unsur nitrogen, kemudian dipreservasi dalam deep freezer (-80oC) selama 7 hari (H7) dan 90 hari (H90). Hasil menunjukkan terdapat variasi respon tumbuh strain-strain Nostoc setelah dipreservasi. Strain yang dipreservasi menggunakan protektan DMSO 5% menunjukkan selisih diameter koloni yang lebih besar, kerusakan filamen lebih sedikit dan kadar klorofil lebih tinggi dibandingkan kontrol negatif.

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ABSTRACTPreservation of culture collections Nostoc done considering that Nostoc is one of microalgae soil that important and useful. Preservation methods commonly used for Nostoc is with periodic subculture, but that methods have short comings vulnerable to loss of genetic stability. Beside that, freezing method is commonly used for Nostoc preservation. Eight Nostoc strains used in preservation by freezing method at temperature -80oC are CPG8, CPG24, BAD5, GIA13a, GIA12- 03, TAB7d, BTM6-01 and TAK23. The addition of the intracellular protectant DMSO 5 % was done to decrease the effects of freezing (cold stress) in Nostoc. For comparison, eight strains were also preserved without using protectant (negative control) in BG 11 nitrogen free medium, then preserved in a deep freezer (-80oC) for 7 days (H7) and 90 days (H90). Results showed variation in response to growing strains Nostoc after preservation. Strains were preserved using DMSO 5% protectant showed difference of colony diameter, filament has less damage and has higher clorophyl value compared with negative control."

"Characterizations have been performed on single stage Transversely Excited Nitrogen Laser of Blumlein type. Optical cavity arrangement is varied prior to measurement which shows no significant increase in energy on both configurations of inserting a mirror only and a pair of mirror and a quartz parallel plate. Frequency repetitions respond reveals a small drop in energy at higher frequency i.e. 10 Hz by a factor of 20%. N2 flow rate consideration behaves on the similar way like pressure profile. At higher supply voltage maximum energy is shifted to higher N2 flow rate. A similar tendency occurs on pressure curve but with more pronounced maximum energy. Higher supply voltage would shift maximum energy to higher N2 pressure. Other operating conditions have been kept constant. Beam divergence measurement has given 1,87 mrad on vertical direction and 9,32 mrad on horizontal axis. However, beam cross section experiences a -10° tilt against horizontal reference. This may happen due to a slight twist on main electrodes. Measurements on different date have showed inconsistent results. Major cause is suspected on using different N2 cylinder, replacement on the gauge pressure, and crater creation on HV side spark gap electrode."

"ABSTRACTTwo laboratory-scale sequencing batch reactors (SBR) arranged in series were used to evaluate bioxidadon and nitrogen removal from a synthetic sewage consisting of acetic acid as the carbon source. Microprocessor based timer were used to control various phases in the SBR?s phases. This paper discusses the result of varying recycle ratio, returned mixed liquor, in bioxidation, denitrification and nitrification process in the modified SBR Generally, as the recycle ratio increased if was found to give a better the removal efficiency in terms of organic carbon and total nitrogen removal. The modified SBR, in general. shows promise as an effective treatment alternative to the conventional activated sludge process."