Biofilm Formation of Pseudomonas geniculata (Wright, 1895) Chester, 1901 on Three Fungals Species: Relationship with Incubation Time and Fungal Diameter Size

Pseudomonas geniculata has been isolated from uncontaminated vertisol in Kulon Progo district. The isolate is hydrocarbonoclastic bacterium capable of forming biofilm on the fungal hyphae. Sinergy of both microbe in the form fungal-bacteria biofilm produce high ability to degrading hydrocarbon and survive in its pollution environment. The purpose of this research was to evaluate ability of Pseudomonas geniculata (Wright, 1895) Chester, 1901 to form biofilm and its attachment on three fungals species such as Penicillium sp., Penicillium funiculosum and Penicillium crustosum. The diameter size of fungal hyphae was of 1.3 µm, 1.9 µm and 2.4 µm, respectively. P. geniculata required at least 48 h to form biofilms on Penicillium sp. hyphae when incubated in mineral Bushnell Haas Medium suplemented with 2 % glucose at room temperature, with maximal biofilm formation being evident at 360 h. Biofilm attachment on Penicillium sp. hyphae was disrupted by the vortex power of 5 rpm for 20 s. Interaction of P. geniculata and Penicillium sp. that has a smallest diameter size of hypha were more successful on biofilm formation and attachment which could contribute to bacterial survival in environmental stresses. Keyword: Biofilm, fungal hyphae, Pseudomonas geniculata (Wright, 1895) Chester, 1901, Penicillium.

Respon Tanaman Jagung yang Dipupuk Bio-fosfat di Andisols

This experiment was aimed to find out the effect of the pellet fertilizer combining of rock phosphate, organic material, and Aspergillus Niger inoculums (bio-phosphate fertilizer) on maize growth and its phosphorus uptake in Andisols. The study was conducted in green house of Faculty of Agriculture of Gadjah Mada University using plastic pots containing 5 kg of Andisols from Salatiga, Central Java. The treatments were bio-phosphate, the pellet of rock phosphate and A. Niger, the pellet of rock phosphate and organic material, the pellet of rock phosphate, super phosphate, and without phosphorus fertilizer arranged using Completely Randomized Design with five replications. Arjuna maize was plant indicator. The results indicated that the bio-phosphate fertilizer increased the maize growth and its phosphorus uptake in Andisols up to 32.0% and 65.1% compared without phosphate fertilizer, respectively

Karakterisasi Dan Identifikasi Isolat Bakteri Pendegradasi Fraksi Aspaltik Hidrokarbon Lumpur Minyak Bumi

Bakteri pendegradasi fraksi aspaltik hidrokarbon minyak bumi diisolasi dari habitat yang belum terpapar minyak bumi yaitu tanah hutan, kompos serta sedimen hutan bakau, lalu dikarakterisasi dan diidentifikasi secara fenotipik dan genotipik. Penelitian ini bertujuan untuk memperoleh bakteri yang potensial mendegradasi fraksi alspaltik. Bakteri diisolasi dari sampel tanah dengan menggunakan medium Bushell-Haas yang mengandung fraksi aspaltik sebagai satu-satunya sumber karbon dan energi. Selanjutnya isolat yang diperoleh diuji kemampuannya mendegradasi fraksi aspaltik dalam media pertumbuhan. Seleksi isolat dilakukan berdasarkan kecepatan pertumbuhan dan kemampuan mendegradasi fraksi aspaltik. Dalam penelitian ini diperoleh 7 isolat, yaitu 3 isolat (HI, H2 dan H3) berasal dari sampel tanah hutan, 2 isolat (Kl dan K2) berasal dari sampel kompos, dan 2 isolat (Bl dan B2) berasal dari sampel sedimen hutan bakau. Berdasarkan kemampuan mendegradasi fraksi aspaltik, diseleksi 5 isolat (H1, K1 ,K2, B1 dan B2) untuk diuji kemampuan degradasinnya serta dikarakterisasi untuk tujuan identifikasi. Uji degradasi menunjukkan bahwa isolat HI adalah yang paling potensial dalam mendegradasi fraksi aspaltik (52,5 %) lalu diikuti oleh isolat Bl (11%), isolat Kl (8,5%), isolat K2 (7,5%) dan isolat B2 (1,5%). Uji kecepatan pertumbuhan juga menunjukkan bahwa isolat HI adalah yang paling unggul(u = 0,109 jam1) lalu diikuti oleh isolatBl (u = 0,091 jam"1), isolatKl (u = 0,080 jam1), isolat K2 (n=0,076 jam1) dan isolat B2 (x=0,080 jam1). Berdasarkan karakterisasi fenotipik dan genotipik, empat isolat (HI, Kl, K2 dan Bl) diidentifikasi sebagai anggota genus Acinetobacter. Dengan demikian, bakteri pendegradasi fraksi aspaltik dapat diperoleh dari habitat alami yang belum tercemar oleh minyak bumi karena adanya kemiripan struktur kimiawi antara fraksi aspaltik dengan asam humat yang merupakan hasil degradasi lignin. Kata kunci: fraksi aspaltik, lumpur minyak bumi, pendegradasi, Acinetobacter

Isolasi dan Seleksi Bakteri dari Sedimen Mangrove untuk Pembentukan Konsorsium Bakteri Perombak Dibenzofuran

Dibenzofuran merupakan salah satu senyawa hidrokarbon aromatis polisiklik (HAP) yang mengandung oksigen. Paparannya di alam harus segera ditanggulangi karena dibenzofuran berperan sebagai prekursor bagi senyawa berkhlor turunannya yang bersifat lebih toksik. Dibenzofuran dapat dijadikan senyawa model karena beberapa bakteri perombak dibenzofuran juga mampu merombak senyawa mirip lainnya seperti dibenzodioksin, fluorena, fluorantena, dibenzofuran terkhlorinasi, fenantrena dan antrasena. Penelitian ini dilakukan untuk membentuk konsorsium bentukan yang mempunyai kemampuan tinggi dalam merombak dibenzofuran. Isolat bakteri diperoleh dari sedimen mangrove asal Balongan, Indramayu, Jawa Barat menggunakan medium mineral cair yang diperkaya dengan dibenzofuran sebagai satu-satunya sumber karbon dan energi. Total 12 isolat bakteri, GMYk-1, GMYk-2, GMYk-3, GMYk-4, GMYk-5, GMYs-1, GMYs-2, GMYs-3, GMYs-4, GMYs-5, GMYs-6 dan GMYs-7 berhasil diisolasi dari sedimen. Berdasarkan pengamatan terhadap keragaman isolat-isolat yang diperoleh serta interaksi di antara isolat dalam merombak dibenzofuran, empat isolat berhasil terseleksi untuk menyusun konsorsium bentukan. Isolat tersebut adalah GMYs-1, GMYs-6, GMYs-7 dan GMYk-1. Berdasarkan kemampuan merombak dibenzofuran dari kombinasi isolat-isolat yang disusun, biakan campuran GMYs-1- GMYs-6-GMYk-1 dipilih sebagai konsorsium bentukan. Konsorsium bentukan mempunyai kemampuan paling tinggi dalam merombak dibenzofuran

Pengaruh Bahan Organik dan Suhu Pengeringan terhadap Ketahanan Hidup Aspergillus niger dalam Pupuk Pelet Bio-fosfat

This research was aimed to investigate the effect of organic matter and drying temperature on Aspergillus niger survivability in the rock phosphate pellet fertilizer namely bio-phosphate. The research was arranged by a completely randomized design 3x3x6. Addition of the mixing of tapioca waste, rice bran, and starch (BOC) and the humic substance (BH) in the bio-phosphate, and its drying temperature (SP) were the treatments. Aspergillus niger inoculums survivability in the bio-phosphate was determined using plating methods. The result showed that the addition of BOC decreased amount of A. niger in the bio-phosphate up to 28.0%, while the BH increased the amount of A. niger up to 24.4%. The ideal drying temperature of bio-phosphate pellet fertilizer was 600C

The Effect of Rock Phosphate and Level of Inoculums on The Survivability of Aspergillus niger and Its Solubilization Ability When Pelleted With Rock Phosphate

The study is intended to examine the survival of Aspergillus niger and its phosphate solubilizing ability when pelletedwith rock phosphate. An A. niger YD 17 obtainedfrom the Laboratory of Microbiology. Faculty of Agriculture, Gadjah MadaUniversity was used. The pellet was made by mixing rock phosphate (80%) with organic matter (J 3. 9% waste of tapioca. 6% rice bran, and 1% starch) and spore of A. niger. The experimental design was the Complete Randomized Design 5x4 with 3 replicatiOns. The first factor was sources of rock phosphate (Christmas Island. Jordan, China, Ciamis, and Madura). The secondfactor was the number ofinoculums i.e. control without inoculums, 107 • J(t and J(t cfu.g·'. The colony of A. niger that formed at medium of potatoes dextrose agar (PDA) and the amount of soluble phosphorus in the Pikovskaya liquid medium were parameters. Experimental results indicated that sources of rock phosphate and the number of inoculums itif1uence the A. niger survivability and its phosphorus solubilizing ability. Rock phosphate from Ciamis gave the best support for fungus survival and rock phosphate from Christmas Island was the best substrate for phosphate solubilization. The highest soluble phosphate was achieved by ul inoculums

Pengaruh Campuran Onggok, Sekam, Pati dan Bahan Humat terhadap Pertumbuhan Aspergillus niger dan Kemampuannya dalam Melarutkan Fosfat

The aims of this study were to investigate the effects of the mixture of tapioca waste, rice bran, starch (BOC), and humic substance (BH) on Aspergillus niger growth and its phosphate solubilizing capability. The experiment was conducted in Erlenmeyer flask containing 200 ml Pikovskaya liquid media and incubated on shaker with 100 rotaries per minute for nine days.  The Christmas Island phosphate rock was used as phosphate source.  Aspergillus niger YD 17 was taken from the Laboratory of Microbiology, Faculty of Agriculture, Gadjah Mada University. The experiment was arranged using factorial completely randomized design with three-replications (3x4x3). The level of BOC (i.e. 0, 2, and 4 g.l-1 media)   and BH   (i.e. 0, 1, 2, and 3 ml.l-1) were applied as experimental factors. Dry weight of mycelia and the soluble phosphate in media were parameters of Aspergillus niger growth. The results showed that BOC and BH increased the Aspergillus niger growth and its phosphate solubilizing capability (P£0.05). Four-gram of BOC and 3 ml of BH per litter of media were the best level for Aspergillus niger growth, while 4 g of BOC and 2 ml of BH was the best level for phosphorus solubilization capability

Pengaruh Campuran Onggok, Sekam, Pati dan Bahan Humat terhadap Pertumbuhan Aspergillus niger dan Kemampuannya dalam Melarutkan Fosfat

The aims of this study were to investigate the effects of the mixture of tapioca waste, rice bran, starch (BOC), and humic substance (BH) on Aspergillus niger growth and its phosphate solubilizing capability. The experiment was conducted in Erlenmeyer flask containing 200 ml Pikovskaya liquid media and incubated on shaker with 100 rotaries per minute for nine days.  The Christmas Island phosphate rock was used as phosphate source.  Aspergillus niger YD 17 was taken from the Laboratory of Microbiology, Faculty of Agriculture, Gadjah Mada University. The experiment was arranged using factorial completely randomized design with three-replications (3x4x3). The level of BOC (i.e. 0, 2, and 4 g.l-1 media)   and BH   (i.e. 0, 1, 2, and 3 ml.l-1) were applied as experimental factors. Dry weight of mycelia and the soluble phosphate in media were parameters of Aspergillus niger growth. The results showed that BOC and BH increased the Aspergillus niger growth and its phosphate solubilizing capability (P£0.05). Four-gram of BOC and 3 ml of BH per litter of media were the best level for Aspergillus niger growth, while 4 g of BOC and 2 ml of BH was the best level for phosphorus solubilization capability

Proteolytic activity of recombinant DegP from Chromohalobacter salexigens BKL5

Background: DegP is a serine protease that specifically cleaves and refolds unfolding proteins in the periplasmic space of the cells. To date, there is no information regarding DegP from halophilic bacteria. Chromohalobacter salexigens BKL5 is a moderately halophilic bacterium that has the ability to grow in a media containing more than 15% salt. Therefore, the objectives of this work were to clone and overexpress DegP-encoding gene from C. salexigens BKL5 and characterize its biochemical properties. Results: DegP-encoding gene was overexpressed in Escherichia coli BL21(DE3) CodonPlus in an active form. SDS-PAGE analysis showed that the molecular weight of the recombinant DegP was 45 kDa. Size-exclusion chromatography analysis suggested that recombinant DegP was present in two multimeric states, hexameric and dodecameric, with molecular weights of 297.9 and 579.12 kDa, respectively. Both conformations were enzymatically active when casein was used as substrate for enzymatic assay. Circular dichroism analysis showed that recombinant DegP was composed of 0.21\u20130.29 helical content, which was comparable to the helical content in the crystal structure of E. coli DegP. The basic/acidic residue ratio of recombinant DegP was 0.56, which was slightly higher than that of DegP from extreme halophiles (average, 0.45) but significantly lower than that of DegP from nonhalophiles (average, 0.94). Conclusions: Recombinant DegP from C. salexigens BKL5 showed proteolytic activity when \u3b2-casein was used as a substrate. In silico analysis indicated that recombinant DegP had characteristics similar to those of halophilic proteins depending on its amino acid composition