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ABSTRACT: Corrosion on metal equipment of natural gas industries, which is caused by microorganism activity, is preceded by the growth of pioneer microorganisms and then followed by the growth of other organisms. The purposes of this research are to reveal microalgae succession process on cold insulation and the outer wall of LNG/LPG tank, as well as to identify the microalgae that involved in the process. The microalgae samples were obtained from PT Badak NGL Bontang, East Kalimantan. Microalgae isolation and identification were done in Laboratory of Microbiology, Center for Biotechnology Study, Gadjah Mada University. Samples were taken from four locations, i.e., upper tank (dome), wet lower tank, dry lower tank and cold insulation, which have the highest microalgae growth. Sampling was done using community change ecological method within 1 m2 plot. Sample plots were clean. The sampling were done every two weeks until two month. The obtained microalgae were identified based on morphological observation according to Humm (1980). Molecular analysis to detect the microalgae community was implemented by using RISA (Ribosomal Intergenic Spacer Analysis). Several kinds of microalgae were found two weeks after cleaning. There were found 4, 2, 4 and 3 genera respectively on dome, wet lower tank, dry lower tank and cold insulation. Fourweeks after cleaning, on dome, wet lower tank, dry lower tank and cold insulation were found 3, 2, 2 and 2 genera respectively. Six weeks after cleaning, there were found 3, 4, 1 and 2 genera respectively on dome, wet lower tank, dry lower tank and cold insulation. In the end of the observation, eight weeks after cleaning, on dome, wet lower tank, dry lower tank and cold insulation were found 4, 4, 3 and 4 genera respectively. After identification, it was found that 61% microalgae not identified. Thirty nine percent microalgae were classified in to the genera of Chroococcus, Lyngbya, Gloeocapsa, Oscillatoria, Gloeotrichia and Trentepohlia. Molecular analysis shows that for some DNA bands. Several kinds of bands were identified two weeks after cleaning. There were found 4, 3, 4 and 4 bands respectively on dome, wet lower tank, dry lower tank and cold insulation. Four weeks after cleaning, on dome, wet lower tank, dry lower tank and cold insulation were found 3, 3, 2 and 3 bands respectively. Six weeks after the cleaning, there were found 3, 2, 2 and 1 bands respectively on dome, wet lower tank, dry lower tank and cold insulation. In the end of the observation, eight weeks after cleaning, on dome, wet lower tank, dry lower tank and cold insulation were found 2, 2,1 and 1 bands respectively. Both morphological observation and molecular analysis indicate the occurrence microalgae succession. The genera of Gloeocapsa were found to be the pioneer microalgae which become dominant at the end of the observation at all sampling locations. Key words : corrosion, microalgae, succession, RISA

Perbandingan jenis media imobilisasi terhadap kinerja proses peruraian anaerob termofilik palm oil mill effluent

A B S T R A C TPalm oil mill effluent (POME) is wastewater with high organic matter, the raw material of biogas production through anaerobic digestion. In anaerobic digestion, the washout effect frequently becomes a problem, along with the increasing organic loading rate (OLR) in a continuous system. Therefore, the addition of immobilization media was carried out to reduce this risk. This study aims to evaluate the effect of immobilization media type and arrangement on the performance of thermophilic anaerobic digestion of POME. Two immobilization media were evaluated,i.e., carbon fiber textile (CFT) media and natural zeolite particles. The anaerobic process performance was determined by measuring the concentration of volatile fatty acids (VFAs), soluble chemical oxygen demand (sCOD), and methane (CH4) yield. This study indicated that the immobilization media led to higher CH4 yields than the reactor without immobilization media. The CH4 yield of the reactor with natural zeolite was 0.3487 L/g sCOD, 0.3050 L/g sCOD in the reactor with CFT media, and 0.2873 L/g sCOD in the reactor without immobilization media. In addition, only natural zeolite can maintain reactor performance when the temperature accidentally increased with a recovery period of 14 days.Keywords: anaerobic digestion; biogas; carbon fiber textile; natural zeolite; POME.ABSTRAKPalm oil mill effluent (POME) merupakan limbah cair dengan kandungan organik yang tinggi sebagai bahan baku produksi biogas melalui peruraian anaerob. Dalam peruraian anaerob, efek washout selalu menjadi masalah seiring dengan meningkatnya organic loading rate (OLR) pada sistem kontinu. Oleh karena itu, dilakukan penambahan media imobilisasi untuk mengurangi risiko tersebut. Penelitian ini bertujuan untuk mengevaluasi pengaruh jenis dan pengaturan media imobilisasi terhadap kinerja peruraian anaerob termofilik POME. Dua media imobilisasi yang diuji yaitu media jenis carbon fiber textile (CFT) dan media berupa partikel zeolit alam. Kinerja proses anaerob ditentukan dengan mengukur konsentrasi asam lemak volatil (VFA), soluble chemical oxygen demand (sCOD) dan yield metana (CH4). Hasil penelitian ini menunjukkan bahwa reaktor dengan media imobilisasi menghasilkan yield CH4 yang lebih tinggi dibandingkan dengan reaktor tanpa media imobilisasi. Yield CH4 reaktor dengan zeolit alam sebesar 0,3487 L/g sCOD, 0,3050 L/g sCOD pada reaktor dengan media CFT dan 0,2873 L/g sCOD pada reaktor tanpa media imobilisasi. Selain itu, hanya zeolit alam yang dapat mempertahankan performa reaktor saat mengalami gangguan peningkatan suhu secara tiba-tiba dengan masa recovery selama 14 hari. Kata kunci: biogas; carbon fiber textile; peruraian anaerobic; POME; zeolit alam

Ethanol Fermentation on Mixed Sugars Using Mixed Culture of Two Yeast Strains

The objective of this study was to evaluate the use of mixed cultures of the recommended yeast strainsfrom a previous study on ethanol fermentation using a substrate mixture consisting of sucrose, glucose, andfructose. There were three mixed (combination) cultures namely OUT7096/OUT7913, OUT7096/OUT7921,and OUT7913/OUT7921. The fermentation medium contained sugar mixture consisting of glucose, fructose,and sucrose with a composition generally close to the composition of sugars in sweet sorghum juice. Overall,fermentation is carried out in two stages. First fermentation was performed using the three mixed culturesto determine the best combination based on the concentration of ethanol produced and the concentration ofresidual sugar. Second fermentation was conducted using the best mixed culture obtained from the fi rst stage.This second stage was intended to describe the pattern of the changes in the concentration of ethanol, sugarsand biomass during the fermentation progresses and to determine some kinetic parameters namely ethanolyield (Yp/s), growth yield (Yx/s) and specifi c growth rate (μ). The results of the fi rst fermentation showed thatthe best mixed culture was OUT7913/OUT7921 and the subsequent fermentation using this culture providethe highest ethanol yield (Yp/s) = 0.47 g.g-1 that was reached at 53rd hour, growth yield (Yx/s) = 0.425 g.g-1, andμ = 0.12 hour-1.Keywords : fermentation, ethanol, mixed culture, mixed suga

Secretion of Organic Acids by Phosphate Solubilizing Bacteria

Phosphorus availability is a major limiting for crop production.  Bacterial solubilization of insoluble inorganic phosphate has been studied as a means of providing available phosphorus for crop production.  Bacterial abilities to solubilize calcium phosphate and rock phosphate have been identified to be related with their abilities to produce gluconic acid and ketogluconic acid.  However, there is no information regarding the relationship between bacterial ability to solubilize aluminum phosphate and their ability to produce organic acids.  This study was conducted to investigate the relationship between bacterial ability to solubilize calcium and aluminum phosphates with their ability to produce organic acids.  Bacterial ability to solubilize calcium and aluminum phosphates were determined as the concentration of soluble phosphate in the filtrate of bacterial cultivation media, while bacterial ability to produce organic acids were assessed from the accumulated organic acids in its.  The results showed that bacterial abilities to solubilize calcium and aluminum phosphates well related to their abilities to produce organic acids.  Organic acids related with the solubilization of calcium phosphate differ from the ones relatedAlam, S., S. Khalil, N. Ayub,  and M. Rashid. 2002. In vitro solubilization of inorganic phosphate by phosphate solubilizing microorganisms (PSM) from maize rhizosphere. Int. J. Agri. Biol. 4: 454-458.Beauchemin, S., D. Hesterberg, J. Chou, M. Beauchemin, R.R. Simard, and D.E. Sayers. 2003. Speciation of phosphorus in phosphorus-enriched agricultural soils using X-ray absorption near-edge structure spectroscopy and chemical fractionation. J. Environ. Qual. 32:1809–1819.Bolan, N.S., R. Naidu, S. Mahimairaja, dan S. Baskaran. 1994. Influence of low-molecular-weight organic acids on the solubilization of phosphates. Biol. Fertil. Soils 18: 311-319.Cline, G.R., P.E. Powell, P.J. Szaniszlo, dan C.P. Reid. 1983. Comparison of the abilities of hydroxamic and other natural organic acids to chelate iron and other ions in soil. Soil Sci. 136: 145-157.Curtin, D., and J.K. Syers, 2001. Lime-induced changes in indices of soil phosphate availability. Soil Sci. Soc. Am. J. 65:147–152.Fox, T.R., N.B. Comerford, dan W.W. McFee. 1990. Phosphorus and aluminium release from a spodic Horizon mediated by organic acids. Soil Sci. Soc. Am. J. 54: 1763-1767.Hue, N.V., G.R. Craddock, dan F. Adams. 1986. Effect of organic acids on aluminium toxicity in subsoils. Soil Sci. Soc. Am. J. 50: 28-34.Johnson, S.E., and R.H. Loeppert. 2006. Role of organic acids in phosphate mobilization from iron oxide. Soil Sci. Soc. Am. J. 70:222–234.Kumari, A., K.K. Kapoor, B.S. Kundu, and R.K. Mehta. 2008. Identification of organic acids produced during rice straw decomposition and their role in rock phosphate solubilization. Plant Soil Environ. 54: 72–77Lopez-Hernandez, D., D. Flores, G. Siegert, dan J.V. Rodriguez. 1979. The effect of some organic anions on phosphate removal from acid and calcareous soils. Soil Sci. 128: 321-326.Lopez-Pineiro, A., dan A. Garcia-Navarro. 2001. Phosphate fractions and availability in Vertisols of South-Western Spain. Soil Sci. 166: 548-556.Olsen, S.R. dan Sommers, L.E. 1982. Phosphorus. In Page, A.L., Miller, R.H. & Keeney, D.R. (eds.). Methods of Soil Analysis. Part 2. 2nd ed. ASA and SSSA Publisher, Madison.Rao, W.V.B.S., and M.K. Sinha. 1963. Phosphate dissolving microorganisms in the soil and rhizosphere. Indian J. agric. Sci. 33: 272-278.Rodriguez, H., T. Gonzalez, I. Goire, dan Y. Bashan. 2004. Gluconic acid production and phosphate solubilization by the plant growth-promoting bacterium Azospirillum spp. Naturwissenschaften 91: 552-555.Sagoe, C.I., T. Ando, K. Kouno, and T. Nagaoka. 1997. Effect of organic-acid treatment of phosphate rocks on the phosphorus availability to Italian ryegrass. Soil Sci. Plant Nutr. 43: 1067-1072.Sanchez, P.A. 1976. Properties and Management of Soils in the Tropics. John Wiley & Sons, Inc. New York. 618 pp.Siddique, M.T., and J.S. Robinson. 2003. Phosphorus sorption and availability in soils amended with animal manures and sewage sludge. J. Environ. Qual. 32:1114–1121.Song, O.R., S.J. Lee, Y.S. Lee, S.C. Lee, K.K. Kim, dan Y.L. Choi. 2008. Solubilization of insoluble inorganic phosphate by Burkholderia cepacia DA23 isolated from cultivated soil. Braz. J. Microbiol. 39: 151-156.Sridevi, M., K.V. Mallaiah, and N.C.S. Yadav. 2007. Phosphate solubilization by Rhizobium isolates from Crotalaria species. J. Plant Sci. 2: 635-639.Traina, S.J., G. Sposito, D. Hesterberg, dan U. Kafkafi. 1986. Effects of pH and organic acids on orthophosphate solubility in an acidic, montmorillonitic soil. Soil Sci. Am. J. 50: 45-52.Trivedi, P., and T. Sa. 2008. Pseudomonas corrugata (NRRL B-30409) mutants increased phosphate solubilization, organic acid production, and plant growth at lower temperatures. Curr. Microbiol. 56: 140-144.Tunesi, S., V. Poggi, and C. Gessa. 1999. Phosphate adsorption and precipitation in calcareous soils: The role of calcium ions in solution and carbonate minerals. Nutr. Cycling Agroecosyst. 53:219–227.Zhang, M., A.K. Alva, Y.C. Li, dan D.V. Calvert. 2001. Aluminium and iron fractions affecting phosphorus solubility and reactions in selected sandy soils. Soil Sci. 166: 940-948.with the solubilization of aluminum phosphate.  Moreover, there is similarity in the production of organic acids related to the solubilization of aluminum phosphates and iron phosphate

Peruraian Anaerobik Termofilik Palm Oil Mill Effluent dengan Variasi Konsentrasi Substrat

High utilization of palm oil in Indonesia corresponds to palm oil mill effluent (POME). The POME has chemical oxygen demand (COD) of up to 100.000 mg/L, which can pollute the ecosystem if not adequately treated. One of the methods to manage POME is anaerobic thermophilic digestion. The advantage of this method is the production of methane gas which is a form of alternative energy. Substrate concentration affects anaerobic digestion. This preliminary experiment aims to evaluate the performance of anaerobic thermophilic digestion on various POME concentrations at 55 °C. The anaerobic digestion was run with 16.000, 11.000 and 5.000 mg sCOD/L substrate concentrations. Digested cow manure (DCM) was used as inoculum. The process was running in a continuous system after 7-days of acclimatization of the batch system. The result shows that 16.000 and 11.000 mg sCOD/L concentrations produced more methane, but the methane yield was not statistically significant with the Tukey test (p=0,05). The POME with a 5.000 mg sCOD/L concentration produced less methane and plummeted after day 85. The lower methane production at lower substrate concentration was due to the low sCOD availability and high volatile fatty acid (VFA) accumulation which inhibited the methane production

Ethanol Fermentation on Mixed Sugars Using Mixed Culture of Two Yeast Strains

The objective of this study was to evaluate the use of mixed cultures of the recommended yeast strainsfrom a previous study on ethanol fermentation using a substrate mixture consisting of sucrose, glucose, andfructose. There were three mixed (combination) cultures namely OUT7096/OUT7913, OUT7096/OUT7921,and OUT7913/OUT7921. The fermentation medium contained sugar mixture consisting of glucose, fructose,and sucrose with a composition generally close to the composition of sugars in sweet sorghum juice. Overall,fermentation is carried out in two stages. First fermentation was performed using the three mixed culturesto determine the best combination based on the concentration of ethanol produced and the concentration ofresidual sugar. Second fermentation was conducted using the best mixed culture obtained from the fi rst stage.This second stage was intended to describe the pattern of the changes in the concentration of ethanol, sugarsand biomass during the fermentation progresses and to determine some kinetic parameters namely ethanolyield (Yp/s), growth yield (Yx/s) and specifi c growth rate (&mu;). The results of the fi rst fermentation showed thatthe best mixed culture was OUT7913/OUT7921 and the subsequent fermentation using this culture providethe highest ethanol yield (Yp/s) = 0.47 g.g-1 that was reached at 53rd hour, growth yield (Yx/s) = 0.425 g.g-1, and&mu; = 0.12 hour-1.Keywords : fermentation, ethanol, mixed culture, mixed sugar</div

Seleksi Isolat Bakteri Amilolitik dari Rhizosfer Canna edulis, Kerr. untuk Produksi Poli Hidroksi Alkanoat dari Limbah Cair Tapioka

Petrochemical-based plastic waste accumulated in landfills have been posing serious threat to the environment as this kind of plastics are non-biodegradable. Replacing petrochemical-based plastics with biodegradable plastics constitutes a challenging solution both in terms of mechanical design of the process and most importantly the availability of powerful local microorganism for the process. Therefore, the current study was searching for appropriate local microorganisms for poly hydroxyl alkanoate (PHA) production from starch waste, which was considered as one of cheap carbon sources. Waste water of cassava industry is a good resource of such starch waste water. The microbes were isolated from Canna edulis, Kerr. rhizosphere from Cangkringan.  The expected isolates were the bacteria enable the coupling of carbon catabolic pathways with PHA anabolic pathways. It was found that ten isolates were able to use waste water of cassava flour industry as carbon source. The PHA quantitative analysis by spectrophotometer showed that the isolate of Bacillus sp. C8 produced the highest PHA of 2,095 g/L. Further FTIR analysis showed specific bands near 1363,67 cm-1, 1641,42 cm-1, 2929,87 cm-1, 3408,22 cm-1 wavelengths which revealed the presence of CH3, ester carbonyl group (C=O), C-H and terminal OH group of PHA. ABSTRAKAkumulasi sampah plastik berbasis petrokimia di tempat pembuangan sampah mengganggu lingkungan karena plastik sifatnya tidak mudah didegradasi secara biologi dan sangat tahan di lingkungan. Penggantian plastik yang berasal dari bahan petrokimia dengan bahan plastik yang mudah terdegradasi secara biologi merupakan tantangan tersendiri, baik dari sisi perancangan proses maupun ketersediaan mikrobia lokal yang sesuai untuk proses tersebut. Oleh karena itu, penelitian ini dilakukan sebagai upaya untuk mendapatkan bakteri lokal penghasil PHA yang mampu mengkonsumsi substrat berupa pati. Substrat pati dipilih karena ketersediaan limbat industri tapioka sebagai bahan baku potensial dan murah untuk produksi PHA. Bakteri amilolitik untuk produksi PHA telah berhasil diisolasi dari rhizosfer Canna edulis, Kerr. di Cangkringan, Sleman, Yogyakarta, Indonesia. Bakteri yang diisolasi merupakan bakteri dengan kemampuan memproduksi PHA dan memiliki kemampuan melakukan rangkaian reaksi pada limbah cair industri tapioka dan rangkaian reaksi pembentukan PHA. Telah berhasil didapatkan 10 bakteri yang memiliki aktivitas amilolitik dan dapat menghasilkan PHA  menggunakan limbah cair industri tapioka. Analisis kuantitatif PHA menggunakan spektrofotometer menunjukkan bahwa isolat Bacillus sp. C8 menghasilkan PHA paling tinggi sebesar 2,095 mg/mL. Analisis hasil metabolism isolat C8 menggunakan FTIR memperlihatkan puncak spesifik 1363,67 cm-1, 1641,42 cm-1, 2929,87 cm-1, 3408,22 cm-1 adalah verifikasi adanya CH3, C=O, C-H dan OH dari PHA

Peningkatan Populasi Bakteri Pendegradasi Hidrokarbon Lumpur Minyak Oleh Penambahan Serasah Tanaman Penutup Tanah

ABSTRACT: A laboratory study was conducted with the aim of evaluating the effect of poultry manure and green manure additions on population growth of microorganisms involve in biodegradation of hydrocarbons contained in drill cuttings. The drill cuttinings was obtained from the Tanjung Santan, East Kalilmantan oil field of UNOCAL. The population growth was assayed by most probable number method on basal medium using extracted hydrocarbon as its sole carbon sources. Addition of green manure (Crotalaria juncea) enhanced population growth of hydrocarbon utilizing bacteria, while addition of poultry waste was not beneficial. Penelitian pada skala laboratorium telah dilakukan untuk mengetahui pengaruh pemberian kotoran ternak unggas dan pupuk hijau terhadap perubahan populasi mikroorganisme yang berperan dalam biodegradasi lumpur minyak. Lumpur minyak diperoleh dari lapangan minyak UNOCAI di Tanjung Santan, Kalimantan Tim ur. Perubahan populasi dikuti dengan cars "most probable number" dalam medium basal yang menggunakan hidrokarbon terekstrak sebagai satu-satunya sumber karbon. Penambahan pupuk hijau (Crotalaria juncea) memacu perkembangan populasi bakteri pengguna hidrokarbon sedangkan penambahan kotoran ternak unggas tidak memberikan pengaruh yang menguntungkan. biodegradai hidrokarbon yang teradpat dalam lumpur minyak. Lum bahan organik terhadap perubahan populasi mikroorganisme yang berperan dalam biodegradasi hidrokarbon yang terdapat dalam lumpur minyak. Penambahan pupuk hijau (Crotalaria jurtcea) memacu perkembangan populasi bakteri pengguna hidrokarbon, sedangkan penambahan kotoran ternak unggas tidak memberikan pengaruh yang menguntungkan

Cloning of Thermostable DNA Polymerase Gene from a Thermophilic Brevibacillus sp. Isolated from Sikidang Crater, Dieng Plateu, Central Java

Thermostable DNA polymerase has an important role for amplifying small amount of DNA through polymerase chain reaction (PCR). Thermophillic bacteria Brevibacillus sp. was isolated from Sikidang Crater, Dieng Plateu, Central Java. Previous study showed that crude protein of the isolate could be used in PCR. Unfortunately, like most native thermostable enzymes, the thermostable DNA polymerase of the isolate is synthesized in a very low level and therefore is cumbersome to purify. The purpose of this research is to clone thermostable DNA polymerase gene of the isolate. The DNA polymerase gene was amplified by means of PCR using spesific primers. The amplified fragment was then isolated, purified, and ligated into the pGEM-T cloning vector. The recombinant plasmid was then transformed to competent E. coli JM109 cells using heat shock method. The cloned thermostable DNA polymerase gene from the thermophilic isolate was then characterized for its nucleotide base sequence. The result showed that the DNA Pol I gene was successfully be amplified from the isolate DNA genom, resulting in ± 2,7 kb DNA fragment in length. Sequence analysis of segment of targeted gene showed high similarity to that of thermostable DNA polymerase genes from other Bacillus.Key words : Thermostable DNA Pol I, Brevibacillus sp., PCR, clonin

Konstruksi Open Reding Frames (ORF) Artifisial Berukuran 798-bp yang Menyandi Protein dengan Urutan Asam Amino Acak

Penyusunan pustaka dari open reading frames (ORF) buatan yang tersusun atas 798 bp (pasangan basa), 576  di antaranya tersusun secara acak, yang mampu menyandi 266 asam amino telah berhasil dilakukan. Dalam upaya penyusunan tersebut diperoleh 32 transforman,  lima di antaranya membawa ORF buatan. Dari kelima transforman yang membawa ORF buatan tersebut, hanya satu transforman yang mampu berekspresi dan menyandi suatu protein. Protein yang dihasilkan memiliki ukuran 17 kDa, berukuran lebih kecil daripada ukuran yang diharapkan yaitu 29 kDa