Identification of"Methyl Formate-Producing Enzyme" in Cell-Free Extract of Pichia Methanolica = Identifikasi"enzim pembentuk metil formar" dari ekstrak sel Pichia methanolica

ABSTRACT: Cell-free synthesis of methyl formate by extract of Pichia methanolica was investigated. It was observed that the addition of formaldehyde could increase the methyl formate-producing activity compared to control experiment which contained methanol as a sole substrate for methyl formate production. On the other hand, the addition of formic acid, formate, and S-formylglutathione or GSH did not increase the activity. Methyl formate-producing activity disappeared upon gel filtration of the cell-free extract on Sephadex G-25. However, the full activity was recovered with the addition of NAD+. These results indicated that methyl formate-producing enzyme was present in cell-free extract. This enzyme was found to be responsible for methyl formate formation from methanol and formaldehyde when its cofactor (NAD+) was available. Based on this finding, the standard assay system for methyl formate-producing enzyme could be constructed. Purification of methyl formate-producing enzyme from cell-free extract was possible due to the availability of the standard assay system constructed in this experiment. Keywords : identificationmethyl formate-producing enzym

Molecular Phylogenetic Classification of Streptomycetes Isolated from the Rhizosphere of Tropical Legume (Paraserianthes falcataria) (L.) Nielsen

Intrageneric diversity of 556 streptomycetes isolated from the rhizosphere of tropical legume was determined by using molecular taxonomic method based on 16S rDNA. A total of 46 isolates were taken to represent 37 colour groups of the isolates. 16S rDNA were amplified and subsequently sequenced and the sequences data were aligned with streptomycete sequences retrieved from the ribosomal data base project (RDP) data. Phylogenetic trees were generated by using the PHYLIP software package and the matrix of nucleotide similarity and nucleotide difference were generated by using PHYDIT software. The results confirmed and extended the value of 16S rDNA sequencing in streptomycete systematic. The 16S rDNA sequence data showed that most of the tested colour group representatives formed new centers of taxonomic variation within the genus Streptomyces. The generic assignment of these organisms was underpinned by 16S rDNA sequence data which also suggested that most of the strains represented new centers of taxonomic variation. The taxonomic data indicate that diverse populations of streptomycetes are associated with the roots of tropical legume (P. falcataria). Therefore, the combination of selective isolation and molecular taxonomic procedures used in this study provide a powerful way of uncovering new centers of taxonomic variation within the genus Streptomyces

Screening for Methanol-Utilizing Yeasts Having Methyl formate-producing activity = Seleksi Khamis pengguna Metanol yang mampu menghasilkan Metil Format

Methanol-utilizing yeasts were screened for methyl formate- producing activity. Eleven strains out of twenty strains of yeasts tested were found to have the activity. Pichia methanolica showed the highest activity, followed by Candida sp. N-16, Candida sp. 1 -B, Pichia pinus, and Candida sp. 25-A, respectively. Methyl formate was found to accumulate in the cultural media of those strains during the course of the their growth in methanol- containing media. Along with the methyl formate-producing activity it wasfoundthat resting cells also had a hydrolyzing |activity against methyl formate. Cultivation and reaction conditions were optimized with respect to methyl formate production. The methyl formate-producing activity was strongly induced by methanol but weakly induced by glycerol. On the other hand, the methyl formate-producing activity was not induced by ethanol and glucose. However, methyl formate- hydrolyzing activity was induced by methanol, glycerol, glucose, and ethanol although with different intensities. Key words: methanol yeast - methyl format

MERCURY REDUCTASE ACTIVITY OF AN INDIGENOUS MERCURY RESISTANT BACTERIAL ISOLATE (Bacillus sp. S1) FROM KALIMAS-SURABAYA AS A POTENTIAL REDUCING AGENT FOR MERCURIAL ION (HG2+)

Mercury reductase activity and Hg2+ lowering capacity of a Mercury Resistant Bacteria (MRB) (Bacillus sp. S1) which was isolated from Kalimas River of Surabaya, Indonesia were studied. The activity was determined by Mercury Reductase Assay System (MRAS) in a solution mixture contained 50 mM PBS (pH ± 7.0), 0.5 mM EDTA, 200 µM MgSO4, 0.1% (v/v) ß-merchaptoethanol, 200 µM NADH2 and 25 mg/L HgCl2 and one volume of crude extract incubated at room temperature for various interval period of time. Mercury reductase activity was measured spectrophotometrically at 340 nm. One unit of reductase activity was defined as one molar of oxidized NADH2 produced per total cell per minute. Results of study showed that, the isolate could resist the concentration of HgCl2 up to 11 mg/L. At 30 minute incubation period at room temperature, the highest mercury reductase activity and the Hg2+ lowering capacity was found to be 0.006 unit/109cell and 1.48 mg/L/109cell/minute, respectively with the reduction efficiency of Hg2+ to Hg0 of 0.18% per minute. Therefore, it can be concluded that the Bacillus sp. S1 isolate could be assumed to be exellent mercury bioremediation agent since it was found to be highly mercury resistant and very efficient to reduce cationic mercury (Hg2+) to elemental mercury (Hg0).Keywords: Kalimas-Surabaya, Bacillus sp. S1, Mercury resistant, Mercury reductas

PROSPEK PEMANFAATAN BAKTERI ENTOMOPATOGENIK SEBAGAI AGENSIA PENGENDALI HAYATI SERANGGA HAMA

Pengembangan budidaya tanaman sayuran merupakan salah satu unsur penting dalam pembangunan pertanian untuk menunjang perekonomian Indonesia. Berbagai jenis serangga hama dapat menyerang tanaman sayuran sehingga mengakibatkan kerugian ekonomi yang besar. Untuk mengendalikan hama tersebut umumnya digunakan insektisida kimiawi. Penggunaan insektisida kimiawi secara luas dan terus menerus memang dapat menekan kerusakan akibat serangan hama. Namun demikian, seiring dengan penggunaan insektisida kimiawi, timbul pula masalah yang serius yaitu terjadinya resistensi dan resurgensi serangga hama, terbunuhnya musuh-musuh alami serangga hama yang kemudian menyebabkan timbulnya hama sekunder, terbunuhnya serangga penyerbuk dan bahaya lain pada ternak dan manusia. Oleh karena itu, diperlukan sekali adanya alternatif baru yang dapat dipakai untuk mengendalikan populasi hama tersebut sampai di bawah batas nilai ambang ekonomi. Pengendalian secara hayati (parasit, predator, agensia patogen) adalah salah satu alternatif yang biasanya dicari karena telah terbukti banyak berhasil dinegara-negara maju. Salah satu spesies bakteri entomopatogenik adalah bakteri pembentuk spora yaitu Bacillus thuringiensis yang merupakan pilihan utama dalam pemanfaatan mikrobia sebagai agensia pengendalianhayati serangga hama. B. thuringiensis dalam proses pertumbuhannya menghasilkan badan inklusi parasporal berupa kristal protein yang dikenal dengan delta-endotoksin dan telah diketahui bersifat toksik terhadap beberapa serangga anggota ordo Lepidoptera, Diptera, dan Coleoptera. Walaupun deltaendotoksin bersifat toksik terhadap serangga sasaran, namun tidak toksik terhadap serangga berguna lainnya, hewan, tanaman maupun manusia. Berdasarkan ciri-ciri khas yang menguntungkan di atas, maka hasil eksplorasi strain-strain baru bakteri entomopatogenik anggota spesies B. thuringiensis telah banyak dimanfaatkan sebagai dasar untuk produksi bioinsektisida komersial. Pencaharian strain-strain baru bakteri entomopatogenik yang bersifat endogenik perlu dilakukan di Indonesia sebagai upaya untuk meningkatkan pengendalian serangga hama secara hayati sebagai alternatif pengganti insektisida kimiawi. Pemanfaatan mikrobia indigenous ini sebagai agensia pengendali hayati merupakan suatu terobosan dalam peningkatan pendayagunaan sumberdaya hayati mikrobia secara lebih intensif untuk menyelamatkan lingkungan hidup dari pencemaran. Makalah ini akan membahas berbagai upaya memperoleh strain unggul B. thuringiensis indigenous Indonesia serta pemanfaatan dan pengembangannya untuk produksi bioinsektisida. Dengan menggunakan dasar-dasar bioteknologi diharapkan akan dapat dihasilkan suatu insektisida mikrobial yang bermanfaat untuk mengendalikan hama tanaman sayuran di Indonesia

The Application of molecular Biology in the development of Strptomycete systematics

ABSTRACT: The application of molecular biology in the field of microbial systematics has been viewed as the renaissance period in unraveling microbial diversity. The most substantial change in microbial sytematics which has brought about by the application of molecular approach is the revolution in basic view of microbial diversity, especially the introduction of species concept based on molecular data. As a result, genomic species concept has been proposed on well defined and universally applicable criteria, notably the estimation of the genetic relatedness between organisms by measuring the degree of homology between their DNA molecules. Consequently, streptomycete systematics has experienced a dramatic change in terms of phylogenetic classification and molecular fingerprinting due to extensive practice of molecular methods. This paper will review the impact of the studies on nucleic acid sequencing and fingerprinting as well as DNA: DNA relatedness on the current status of the streptomycete systematics which is the basic tools to unravel streptomycete diversity in natural habitats. Keywords:microbial systematicsphylogeneticgenomic species coru:eptstreptomycetenucleic acid sequencingfingerprintin

Isolasi, Seleksi, Karakterisasi Dan Identifikasi Bakteri Asam Laktat Penghasil Bakteriosin Dari Berbagai Buah Masak

ABSTRACT Fruits are indicates as a habitat of lactic acid bacteria (LAB) because their chemical composition and micro environtment which needed to their life. The aim of this research was to study the diversity of lactic acid bacteria on some ripe fruits, to obtain lactic acid bacterial isolate which capable to produce bacteriocin, to know their phenothypic characteristic, classify an identify the isolates phenetically. Lactic acid bacteria were isolated from papaya, banana, pineapple and salak by using pour plate method and then purified by using streak plate method. All isolates were screened their potency to onhibit the growth of some pathogenic bacteria. The capacity to produce bacteriocin were determined by heating the cultural medium at 100°C up to 60 minutes and treating with the proteolytic enzyme (Proteinase K) at room temperature. The result of this experiment indicated that cultural medium from twelve isolates able to inhibit the growth of Staphylococcus aureus FNCC 0047. the best two of isolates (PE6 and PE9) also active to some pathogenic bacteria such as Eschericia coli FNCC 0091, Bacillus cereus FNCC 0057 and Salmonella tiphymurium FNCC 0050. the inhibitory compounds produce by the isolates... Keyword: Latic acid bacteria (LAB), bacteriocin, staphylococcus aureus FNCC 004

BAKTERI LAUT ISOLAT PULAU PARI PENDEGRADASI KOMPONEN CRUDE OIL

Dalam upaya untuk melakukan bioremediasi tumpahan minyak bumi dilakukan penelitian bakteri laut yang mampu mendegradasi komponen crude oil yaitu phenanthrene, DBT, dan paraffin. Sampel air laut Pulau Pari, DKI Jakarta diaklimasi dalam column reactor selama 2 bulan dengan 6 variasi fertilizer (Super IB, NH4NO3, Uric Acid, Hi-Control, Osmocoat, dan Chitosan). Kemudian sampel bakteri diisolasi pada medium ONR7a padat yang ditambah dengan 100 μl crude oil. Bakteri potensial pendegradasi crude oil diisolasi dan dipurifikasi pada medium marine agar secara streak plate dan disubkultur. Enambelas isolat terpilih diuji kemampuannya mendegradasi phenanthrene, DBT, dan paraffin. Isolat bakteri terpilih yaitu Dn yang terbukti dapat mendegradasi ketiga komponen crude oil. Selanjutnya isolat bakteri tersebut diuji pertumbuhannya pada 5 macam medium yaitu marine broth, polypepton, medium yang mengandung phenanthrene, DBT, dan paraffin. Uji pertumbuhan dilakukan pada kadar NaCl 2% dan 5% pada suhu 30°C serta rasio C/N/P = 100:20:3. Hasil penelitian menunjukkan bahwa pertumbuhan bakteri tercepat pada medium yang mengandung DBT dengan kadar NaCl 2% (g = 3,029 jam), sedangkan pada medium yang mengandung paraffin kadar NaCl 2% memerlukan waktu pertumbuhan terlama (g = 9,342 jam). Pengukuran kemampuan sel bakteri melekat pada hidrokarbon (MATH) menunjukkan bahwa nilai adhesi tertinggi terhadap substrat phenanthrene yaitu 89,23%. Berdasarkan karakterisasi morfologi koloni, morfologi sel, pengecatan gram, karakterisasi fenotipik dengan kit API 20 NE, diketahui bahwa isolat Dn berbentuk diplococcus, bersifat gram negatif, dan bersifat denitrifier. Identifikasi molekular berdasarkan sequencing 16S rRNA dan konstruksi phylogenetic tree menunjukkan bahwa isolat Dn sangat mirip dengan Marinobacter hydrocarbonoclasticus ATCC 27132T. Dapat disimpulkan bahwa isolat bakteri laut di perairan Pulau Pari yang diaklimasi dalam colum reactor beranekaragam dan terdapat isolat bakteri Dn yang mampu mendegradasi ketiga komponen crude oil dengan penambahan sumber N dan P

Isolasi dan Karakterisasi Jamur Pendegradasi Katekin dari Seresah Pinus

Isolation of catechin-degrading fungus from pine litter samples was done using minimal medium that containing catechin as sole carbon and energy source.  A total of 53 isolates were chosen to represent different colonial types of catechin degrading-fungus. The isolates were screened for their ability to degrade catechin in three stages. The first stage of screening was based on their ability to grow on solid medium containing 2 mM, and as a result, 28 isolates were selected.  The second stage of screening on the same medium but containing 4 mM of catechin resulting in 14 selected isolates. The third stage screening was based on their mean growth rate constant (k), instantaneous growth rate constant (m) and generation time (g) on minimal medium containing 4 mM catechin. The result showed that four isolates (D9, K2, K11, and S11) were the best catechin degradator. Further growth kinetic study  (k, m ,and g) of selected  isolates   indicated that  D9, K2, and S11 grew well on the medium containing 40 mM, but  K11 was inhibited by concentration of higher than 10 mM. Catechin biodegradation process was determined by following the decrease of catechin concentration on liquid medium. It was found that isolate K2 had higher ability to degrade catechin than the isolate K11. Finally, the four selected isolates from the third stage were characterized in terms of macroscopic, microscopic and phenotypic characters and identified. The result of the study showed that the isolates D9, K2 and S11 were identified as member of Aspergillus niger group. The isolate D9 was very similar to isolate S11, while the isolate K2 was found to be the most similar with Aspergillus niger van Tiegh. IFO 6341. The isolate K11 was assigned to be member of the genus Trichoderma

Bacillus Resistance and Potensial as Chromium (Cr) Bioremoval

Chromium is one of heavy metal that encountered environment from industrial waste so it can contaminate the environment. Chromium resistance bacteria can transform Cr(VI) to Cr(III). The aim of this research is to find out chromium resistance and bioremoval potential of Chromium by Bacillus. This research was started with resistance assay of 6 isolates Bacillus to determine growth ability of isolates on medium contained Chromium. Range finding test were done to determine heavy metal concentration that used in research and determine 3 isolates that more resistance than others. Growth curves were measured by OD using spectrophotometer UV-Vis. Chromium bioremoval was measured by Atomic Absorption Spectroscophy method. Viability assay was done by pour plate method. Bacillus S1, DA11 and SS19 resistance to nutrient agar-chromium 150 mg/L. Bacillus DA11 got highest bioremoval efficiency in the amount of 76.8% at concentration 38.8 mg/L, while at concentration 1.9 mg/L the amount of bioremoval efficiency were same for all isolates. Chromium concentration were significantly influence the amount of bioremoval efficiency, while type of isolates were not significantly influenc