Yazar "Guven, Reyhan Gul" seçeneğine göre listele

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    Acinetobacter mesopotamicussp. nov., Petroleum-degrading Bacterium, Isolated from Petroleum-Contaminated Soil in Diyarbakir, in the Southeast of Turkey
    (Springer, 2020) Acer, Omer; Guven, Kemal; Poli, Annarita; Di Donato, Paola; Leone, Luigi; Buono, Lorena; Guven, Reyhan Gul
    A new petroleum-degrading bacterium, designated strain GC2(T), was isolated from Bozkus 1 petroleum station in Diyarbakir, located in the southeast of Turkey. Cells were Gram-negative staining, aerobic, coccoid-rods, non-motile, non-spore-forming. The bacterium was found to degrade 100% ofn-alkanes ranging from C11 to C34 presented in the 1% crude oil after incubation of 7 days. The membrane phospholipids were 1,2 diacylglycero-3-phosphorylethanolamine (PEA), phosphatidylglycerol (PG), dipalmitoyl-sn-glycerol 1- phosphocholine (PC1), 1,2 dipalmitoyl-sn-glycero-3-phosphocholine monohydrate (PC3), cardiolipin also called diphosphatidylglycerol (CL) and l-alpha- phosphatidic acid, dipalmitoyl (AP); predominant respiratory ubiquinone was Q-8 and C16:0, C18:1 omega 9c and C16:1 were the major cellular fatty acids. The 16S rRNA sequence analysis revealed that the strain GC2(T)was a member of genusAcinetobacterand was most closely related toAcinetobacter lwoffiiDSM 2403( T)(99.79%),Acinetobacter pseudolwoffiiANC 5318( T)(98.83%) andAcinetobacter harbinensisHITLi 7( T)(98.14%). TherpoBandgyrBgene sequence analysis confirmed that the strain GC2(T)was a member of genusAcinetobacterand that the closest relative wasAcinetobacter lwoffiiDSM 2403( T)(99.08% and 100% similarity, respectively). DNA-DNA hybridization values between GC2(T)and its closest relatives ranged from 65.6% (withA. lwoffii) to 5.1% (withA. venetianus). The whole genome sequence of strain GC2(T)was obtained. The DNA G + C content of this strain was determined to be 42.9 mol %. ANI indexes, in silico estimations of DDH values and wet lab DDH values demonstrated that strain GC2(T)represents an independent genomospecies. On the basis of phenotypic characteristics, chemotaxonomic, phylogenetic data and DNA-DNA hybridization and whole genome analysis, we propose to assign strain GC2(T)as a new species of the genusAcinetobacter, for which the nameAcinetobacter mesopotamicussp. nov. is proposed. The type strain of this species is GC2(T)(DSM 26953 T = JCM 31073 T). The whole genome of strain GC2(T)has been deposited at DDBJ/ENA/GenBank under the accession JAALFF010000000.
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    Barrier height enhancement of metal/semiconductor contact by an enzyme biofilm interlayer
    (Taylor & Francis Ltd, 2013) Ocak, Yusuf Selim; Guven, Reyhan Gul; Tombak, Ahmet; Kilicoglu, Tahsin; Guven, Kemal; Dogru, Mehmet
    A metal/interlayer/semiconductor (Al/enzyme/p-Si) MIS device was fabricated using -amylase enzyme as a thin biofilm interlayer. It was observed that the device showed an excellent rectifying behavior and the barrier height value of 0.78eV for Al/-amylase/p-Si was meaningfully larger than the one of 0.58eV for conventional Al/p-Si metal/semiconductor (MS) contact. Enhancement of the interfacial potential barrier of Al/p-Si MS diode was realized using enzyme interlayer by influencing the space charge region of Si semiconductor. The electrical properties of the structure were executed by the help of current-voltage and capacitance-voltage measurements. The photovoltaic properties of the structure were executed under a solar simulator with AM1.5 global filter between 40 and 100mW/cm(2) illumination conditions. It was also reported that the -amylase enzyme produced from Bacillus licheniformis had a 3.65eV band gap value obtained from optical method.
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    Characterisation of a partially purified protease from Bacillus cereus KG5 isolated from a hot spring
    (Elsevier Sci Ltd, 2011) Ahmetoglu, Nazenin; Bekler, Fatma Matpan; Guven, Reyhan Gul; Acer, Omer; Guven, Kemal
    [Abstract Not Available]
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    Effects of Various Inhibitors on ?-galactosidase Purified from the Thermoacidophilic Alicyclobacillus acidocaldarius Subsp Rittmannii Isolated from Antarctica
    (Korean Soc Biotechnology & Bioengineering, 2011) Guven, Reyhan Gul; Kaplan, Alevcan; Guven, Kemal; Matpan, Fatma; Dogru, Mehmet
    beta-Galactosidase purified from the thermoacidophilic Alicyclobacillus acidocaldarius subsp. rittmannii isolated from Antarctica is a member of the GH42 family. The enzyme was not effected by various concentrations of its reaction product glucose, but was greatly inhibited by the other reaction product galactose using both substrates, ONPG and lactose. Linewever-Burk plot analysis derived from both ONPG and lactose hydrolysis results showed that galactose is a mixed-type inhibitor of the purified beta-galactosidase. The enzyme was slightly activated by Mg(2+) (13% at 20 mM), while inhibited at higher concentrations of Ca(+2) (33% at 10 mM), Zn(+2) (86% at 8 mM) and Cu(+2) (87% at 4 mM). The enzyme activity was not significantly altered by the metal ion chelators EDTA and 1,10-phenanthroline up to 20 mM, indicating that this enzyme is not a metalloenzyme. 2-Mercaptoethanol and DTT were found to enhance beta-galactosidase activity, while p-chloromercuribenzoic acid (PCMB) completely inhibited enzymatic activity (97% at 1 mM; 99.7% at 2 mM), indicating at least one essential Cys residue modified by the reagents in the active site of beta-galactosidase. Iodoacetamide and N-ethylmaleimide had little effect on the beta-galactosidase. Phenylmethylsulfonyl fluoride (PMSF) inhibited the enzyme strongly (19.8% at 1 mM; 71.9% at 10 mM), also showing the participation of serine for enzyme activity.
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    Geobacillus subterraneus subsp aromaticivorans subsp nov., a novel thermophilic and alkaliphilic bacterium isolated from a hot spring in Sirnak, Turkey
    (Microbiol Res Foundation, 2012) Poli, Annarita; Guven, Kemal; Romano, Ida; Pirinccioglu, Hamsi; Guven, Reyhan Gul; Euzeby, Jean Paul Marie; Matpan, Fatma
    A new thermophilic spore-forming strain Ge1(T) was isolated from the Guclukonak hot spring in Sirnak, Turkey. The strain was identified by using a polyphasic taxonomic approach. Strain Ge1(T) was Gram-positive, spore-forming, alkaliphilic rod-shaped, motile, occurring in pairs or filamentous. Growth was observed between 30 and 65 degrees C (optimum 60 degrees C) and at pH 5.5-10.0 (optimum pH 9.0). It was capable of utilizing starch, growth was observed at 0-3% NaCl (w/v) and was positive for catalase and urease. The major cellular fatty acids were iso-C-15:0 and iso-C-17:0, and the predominant lipoquinone found was menaquinone MK7 type. The DNA G+C content of the genomic DNA of strain Ge1(T) was 52.0%. Comparative 16S rRNA gene sequence studies showed that the isolate belonged to the genus Geobacillus. The DNA-DNA hybridization mean values between the representative strain Ge1(T) and the closely related species G. subterraneus, G. thermodenitrificans, G. thermocatenulatus, G. vulcani and G. thermoleovorans were 69.3%, 57%, 37%, 27% and 26%, respectively. The results of DNA-DNA hybridization, physiological and biochemical tests allowed genotypic and phenotypic differentiation of strain Ge1(T). Based on these results, we propose assigning a novel subspecies of Geobacillus subterraneus, to be named as Geobacillus subterraneus subsp. aromaticivorans subsp. nov. with the type strain Ge1(T) (DSM 23066 (T)= CIP 110341(T)).
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    Isolation and cloning of extracellular thermostable ?-galactosidases from a newly isolated Thermophilic Bacillus licheniformis KG9
    (Elsevier Sci Ltd, 2011) Bekler, Fatma Matpan; Stougaard, Peter; Guven, Reyhan Gul; Guven, Kemal
    [Abstract Not Available]
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    Isolation and identification of petroleum degrading bacteria
    (Elsevier Sci Ltd, 2011) Guven, Reyhan Gul; Bekler, Fatma Matpan; Kaya, Hasan; Acer, Omer; Guven, Kemal; Temel, Hamdi
    [Abstract Not Available]
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    Purification and characterization of novel ?-amylase from Anoxybacillus ayderensis FMB1
    (Taylor & Francis Ltd, 2021) Bekler, Fatma Matpan; Guven, Kemal; Guven, Reyhan Gul
    The thermophilic amylase producing Anoxybacillus ayderensis FMB1 was isolated from Sorgun Hot Spring in Turkey. In order to obtain improved production of the enzyme for cost-effective process, optimization of the process parameters is required. Optimum conditions for amylase production were determined using the traditional Submerged Fermentation (SmF) method. The maximum amylase activity was 295.8 U/mg, under the optimized conditions (24-h, 55 degrees C, and pH 8.0) in liquid BMB medium. The best enzyme production was obtained in the presence of 1.5% soluble starch as carbon source and 1% yeast extract as nitrogen source. Enzyme was produced under optimal conditions and partially purified. Partially purified enzyme was stable for up to 120 minutes at 50 degrees C, and its stability was found to be pH 5.0-10.0. Regarding the effects of some metals and chemicals on the activity of the partially purified enzyme, Ca2+ increased the activity by 21%, but enzyme activity was decreased by Mg2+, Zn2+, Ni2+, and Cu2+ by 5%, 29%, 57%, and 64%, respectively. and the enzyme activity was completely inhibited by Hg2+. In addition; DTT, PMSF, PCMB, SDS and EDTA caused a decrease in enzyme activity by 3%, 4%, 12%, 27% and 77%, respectively. The molecular weight of enzyme was found to be 58.5 kDa by SDS-PAGE. The results obtained show that the thermophilic A. ayderensis FMB1 and their enzyme have biotechnological importance.