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Öğe Assessment of heavy metal levels in sediment samples of Kapulukaya Dam Lake (Kirikkale) and lower catchment area(Springer, 2013) Kankilic, Gokben Basaran; Tuzun, Ilhami; Kadioglu, Yusuf KaganIn this study, the concentrations of 13 elements (Al, Fe, Mn, Cr, Ni, Zn, Co, As, Pb, Cu, Mo, Hg, and Cd) were determined in the sediments of three different sites in the Kapulukaya Dam Lake between May 2007 and November 2008. They ranged from 1.47 to 4.64 for Al, 0.92 to 3.48 for Fe (in percent), 326.60 to 1053.00 for Mn, 98.00 to 1,116.00 for Cr, 24.70 to 127.10 for Ni, 14.80 to 124.20 for Zn, 11.0 to 43.20 for Co, 5.00 to 29.30 for Cu, 9.10 to 69.70 for As, 8.60 to 34.00 for Pb, 2.50 to 5.20 for Mo, 1.00 to 1.60 for Hg, and 0.50 to1.80 for Cd in microgram per gram dry weight sediment. The contamination degree of the sediment was assessed on the basis of enrichment factor and corresponding sediment quality guideline. The calculated enrichment factors (EF, measured metal vs. background concentrations) indicated that the effect of man-made activities on the occurrence of concentrations could be accounted for the majority of heavy metals namely Mn, As, Ni, Cu, Zn, Cr, Co, Mo, and Cd, whereas such affect was not detected for Hg and Pb. The maximum values of the EF were represented by As, minimum values by Hg at all sites. Mean EF values were 36.60 and 0.70 for As and Hg, respectively. This study has clearly assessed a certain level of heavy metal pollution in the region, based particularly on the findings from sediment.Öğe Determination of carotenoids in two algae species from the saline water of Kapulukaya reservoir by HPLC(Taylor & Francis Inc, 2018) Aluc, Yasar; Kankilic, Gokben Basaran; Tuzun, IlhamiThe local algae species, Chlorella vulgaris and Scenedesmus regularis, from a highly saline water body of Kapulukaya Reservoir were isolated to analyze their carotenoid composition and content using HPLC method. The gradient solvent system of methanol-acetonitrile-water (84:14:2, v/v/v) and methylene chloride (100%), used to resolve a range of carotenoids from the saponified cells, proved an acceptable separation as inferred from the retention factor (k) ranging between 0.75 and 7.76 and the separation factor (alpha) values greater than 1. Resolution peaks assigned to carotenoids, 21 for C. vulgaris extracts and 22 for S. regularis extracts, were reached within the duration time of 45 min. Main carotenoids identified either tentatively or positively were all-trans-lutein, 9- or 9'-cis-lutein, 13- or 13'-cis-lutein, cis-lutein, All-trans-alpha-carotene, 9- or 9'-cis-alpha-carotene, All-trans-beta-carotene, 9- or 9'-cis-beta-carotene in the species except for all-trans-beta-cryptoxanthin found only in S. regularis. Auroxanthin, neochrome, neoxanthin, and cis-neoxanthin were identified as epoxy-containing compounds. Quantitatively, C. vulgaris was distinguished to have greater amount of lutein and cis-isomers (2.74 mg/g), 77.89% while S. regularis was predominated by beta-carotene and cis isomers as major component, being 80.72% (5.76 mg/g) in total carotenoids (TC). In terms of total carotenoids, the species were considered to be efficient sources for further practical applications.Öğe Determination of the chemical composition in the kapulukaya reservoir sediment by using the pedxrf method(Parlar Scientific Publications (P S P), 2011) Basaran, Gokben; Tuzun, Ilhami; Toyran, Kubilay; Kadioglu, Yusuf KaganIn this study a multi-element analysis was conducted on the contents of the sediments found at three different sites in the Kapulukaya Dam Lake between May 2007 and November 2007. The elemental analysis of the sediment samples was carried out by using the technique of Polarized Energy Dispersive X-ray Fluorescence (PEDXRF). Of twenty three elements, Cr, Ni, Hg demonstrated high levels of contamination at all sites and As at site 3 according to the criteria set for threshold effect concentrations and probable effect concentrations. The accuracy and precision of the technique employed for conducting the chemical analysis were demonstrated by analyzing the G01-GSD-09 sediment and the K04-NIST-2704 river sediment. Measured concentrations reached at average of 92.7 % and 89.9 % accuracy on the standards used, respectively. The present investigation revealed the effectiveness of this technique in analyzing the sediment content.Öğe Magnetite Fe3O4 nanoparticles impregnated on Chlorella vulgaris microalgae: Its role in obtaining hydrogen from the sodium borohydride-hydrolysis(Elsevier, 2024) Duman, Sibel; Kaya, Bulent; Caf, Fatma; Kok, Osman; Tuzun, IlhamiRecently, the single-celled green freshwater microalgae species Chlorella vulgaris has attracted the attention of researchers due to its different usage areas. In particular, research focuses on the technology of obtaining bio-hydrogen with various techniques. This research involves, for the first time, the use of the microalga Chlorella vulgaris as a bio-supporting material for magnetite Fe3O4 3 O 4 nanoparticles (Fe3O4NPs@Chlorella 3 O 4 NPs@ Chlorella vulgaris) ) and the production of hydrogen through catalytic hydrolysis of NaBH4 4 (sodium borohydride, SB) in the presence of the resulting magnetite nanoparticles. Here, detailed kinetic studies were carried out during the SB-hydrolysis by taking magnetite Fe3O4NPs@Chlorella 3 O 4 NPs@ Chlorella vulgaris and SB in varying amounts and at varying temperatures, and the activation energy and lifetime of magnetite Fe3O4NPs@Chlorella 3 O 4 NPs@ Chlorella vulgaris was found to be 23.49 kJ mol-1- 1 and 93,280 mol H2 2 (mol Fe3O4)-1 , 3 O 4 )- 1 , respectively. No change in the chemical and physical structure of the biocatalyst was observed during the hydrolysis of SB, so only detailed characterization of microalgae and magnetite Fe3O4NPs@Chlorella 3 O 4 NPs@ Chlorella vulgaris was performed, and the particle size of the catalyst was calculated as 10.19 +/- 2.17 nm. The results showed that these Fe3O4NPs@Chlorella 3 O 4 NPs@ Chlorella vulgaris , , which can be easily separated magnetically and have high catalytic activity, are a clean and quite surprising catalyst in terms of hydrogen production.Öğe Phragmites australis: An alternative biosorbent for basic dye removal(Elsevier Science Bv, 2016) Kankilic, Gokben Basaran; Metin, Aysegul Ulku; Tuzun, IlhamiThis study is aimed at investigating the removal of methylene blue (MB) from aqueous solutions using a reed species, Phrag-mites australis as an adsorbent. P. australis was modified by means of a chemical treatment, assuring the alteration of hydroxyl groups to sulphonyl groups. Experiments were performed in the batch mode to determine the adsorption dynamics of the modified and untreated P. australis. The impact of several influential parameters such as initial pH, initial dye concentration and contact time on the adsorption capacity of P. australis was evaluated. The adsorption capacity of raw P. australis was found to improve significantly by modification reaction. The maximum sorption capacities of the raw and modified biomass were found to be 22.7 mg/g and 46.8 mg/g at initial MB concentration of 250 ppm, biosorbent dosage 0.25 g and initial dye solution of pH of 6.5, respectively. Dye adsorption equilibrium data were fitted well to the Langmuir isotherm rather than the others. The rate of adsorption followed the pseudo second-order kinetic model. Thermodynamic parameters for both raw and modified biomass showed that the adsorption of MB was favorable and spontaneous. Results showed that both P. australis and its modified form have a potential as an eco-friendly adsorbent for the removal of methylene blue from aqueous solution. (C) 2015 Elsevier B.V. All rights reserved.Öğe Two pronounced Chlorella strains for efficient biodiesel feedstock production(Tubitak Scientific & Technical Research Council Turkey, 2019) Tuzun, Ilhami; Cakmak, Zeynep Elibol; Young, Emmanuel; Cakmak, TurgayIn this study, two indigenous Chlorella strains were evaluated for triacylglycerol (TAG) production and related parameters during 10 days of N-deprivation. The strains were identified based on morphological characteristics and genomic information, named as Chlorella sp. IMU12 and Chlorella sp. IMU17. Time-dependent reduction of growth was accompanied by decreased chlorophyll content, reduced oxygen evolution ratio, and elevated carotenoid content of both strains cultivated in N-free Bold's basal medium. Nitrogen deprivation induced total lipid and neutral lipid content in both strains, supported by FTIR measurement of TAGs. Chlorella sp. IMU17 showed higher production of TAGs as a response to N-deprivation. Strikingly, relative polysaccharide content showed a rapid increase on the first days and a noticeable reduction was recorded especially after 5 days of N-deprivation while TAG production showed a gradual increase during the whole period of N-deprivation in both strains. Starch might be a predominant form of carbon storage in the short term and the continuous increase of TAG production might be supported by degradation of starch in a longer period of N-deprivation. FAME analysis of lipids showed that the saturation level of the fatty acids of both strains meets the European standard EN 14214 requirements. Lastly, N-deprivation stimulated a significant reduction of PUFA production in Chlorella sp. IMU17. Thus, Chlorella sp. IMU17 might stand as a promising candidate for biodiesel feedstock production with its low PUFA content and a concomitant induction of saturation of fatty acids as a clear response to N-deprivation.
