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Öğe An Alternative Approach to the Traditional Mixotrophic Cultures of Haematococcus pluvialis Flotow (Chlorophyceae)(Korean Soc Microbiology & Biotechnology, 2010) Goksan, Tolga; Ak, Ilknur; Gokpinar, SevketIn traditional mixotrophic cultures of microalgae, all the inorganic nutrients and organic carbon sources are supplied in the medium before inoculation. In this study, however, an alternative approach was adopted in Haematococcus pluvialis Flotow, a microalga capable of growing mixotrophically on sodium acetate (Na-Ac). First, the cells were grown under 75 mu mol photons m(-2) s(-1) phototrophically without Na-Ac until the stationary phase and then exposed to five different light regimes by the addition of Na-Ac (e.g., dark, 20, 40, 75, and 150 mu mol photons m(-2) s(-1)). Dry weight (DW), pigments, and especially cell number in alternative mixotrophy (AM) were higher than traditional mixotrophy (TM). Cell number in AM almost doubled up from 21.7 to 42.9x10(4) cells/ml during 5-day exposure to Na-Ac, whereas the increase was only 1.2-fold in TM. Maximum cell density was reached in 75 mu mol photons m(-2)s(-1) among the light intensities tested. We propose that Na-Ac in TM of H. pluvialis can not be utilized as efficiently as in AM. With this respect, AM has several advantages against TM such as a much higher cell density in a batch culture period and minimized risk of contamination owing to the shorter exposure of cells to organic carbon sources. In consequence, this method may be used for other strains of the species, and even for the other microalgal species able to grow mixotrophically.Öğe Comparison of the growth characteristics in two different Spirulina platensis strains(Ege Univ, 2006) Kilic, Cenker; Goksan, Tolga; Ak, Ilknur; Gokpinar, SevketThe cultivation of Spirulina platensis, which is often used in microalgal biotechnology, has successfully been carried out in our country as well. In this study, the growth characteristics of two Spirulina strains in straight and spiral forms were investigated. In addition, spectrophotometric measurements, which make the measurements of chlorophyll and dry weight more practical, were studied. It was found that all the parameters except the cell count were similar during the experiment. While the spiral/straight form ratio was 2.43 at the beginning of the experiment, it increased up to 5.53 at the end. Spectrophotometric measurements are of importance in terms of practicality in the monitoring of the growth in the cultures. In this respect, a strong correlation was determined between the absorbance values at 680 nm and the amounts of dry weight and chlorophyll (p<0.05). As a result, though there was not a significant difference between the growth parameters of the both forms, the use of straight one would be better due to the problems encountered during harvesting.Öğe Cost-effective production of Arthrospira (Spirulina) platensis(WFL Publisher Ltd., 2013) Ak, Ilknur; O?uz, Merve; Benas, Koray; Göksan, TolgaThis study investigated the effects of ammonium nitrate (AN) and agricultural N:P:K (10:10:40) fertilizer (AF) on the growth and pigment composition of Arthrospira platensis Geitler. In the first experiment, the maximum cellular concentration was observed in group AN2, and differed significantly from the control group (p<0.05). The ammonium nitrate concentrations of groups AN1-3 promoted growth. The concentrations of ammonium nitrate in groups AN4-6 inhibited the growth, and these trials had to be ended at day 6. However, no significant differences were found between the group AN2 and the control in terms of the specific growth rate, or chlorophyll a content. In the second experiment, agricultural fertilizer was used as N:P:K source. Among the experimental groups, the highest cell concentration and yield of biomass on nitrogen were determined in group AF3 (p<0.05). There were no significant differences between group AF3 and control in terms of the specific growth rate and chlorophyll a content (p>0.05). Consequently, the results demonstrate that ammonium nitrate or agricultural fertilizer can be used to culture A. platensis and to reduce the cost of producing biocompounds.Öğe Determination of Absorption Coefficient of Chlorella Vulgaris and Arthrospira Maxima in Water(Amer Inst Physics, 2018) Tekiner, Murat; Kurt, Mustafa; Ak, Ilknur; Kurt, ArzuSafe drinking water is crucial for human healthy, nowadays all drinking and irrigation water in developed country commonly come from dams. The water is transported to our usage area by several type of pipe or water-trench. The water can be infected some bacteria such as Chlorella vulgaris, Arthrospira maxima, during this transportation. In this study, we determine which wavelength effect to these green algae and cyanobacteria. For different concentration of these microorganisms in water, we determined uv-vis spectrum. By analyzing these spectrums, we determined absorption coefficient of these microorganisms for selected wavelength. The results show which wavelength can be used for destroy these microorganisms in affected water.Öğe Effect of an organic fertilizer on growth of blue-green alga Spirulina platensis(Springer, 2012) Ak, IlknurIn this study, the influence of an agricultural liquid organic fertilizer on growth and biomass composition of Geitler was studied. In the first trial, five concentrations of organic fertilizer were arranged, e.g., 0.1, 0.25, 0.5, 1 and 2 ml/l, in which no other extra nutrients except bicarbonate were used. Maximum dry weight, chlorophyll and specific growth rate were achieved in control group. In the second trial, initial fertilizer levels of the three groups were 0.1 ml/l and all groups contained sodium bicarbonate. One of the groups had 2.5 g/l NaNO3, while the other was supported with 0.1 ml/l fertilizer by two-day intervals to see the effect of nitrogen. In order to understand the effects of phosphate, 0.4 g K2HPO4 was added to the other group as well as 2.5 g NaNO3. Between the experimental groups, the highest chlorophyll value was found in control group as 53.97 mg/l. The chlorophyll value at group II (37.65 mg/l) was lower than the control group. The maximum dry weight and crude protein recorded in control group were 1,330 mg/l and 60.17%, respectively, when compared with 1,256 mg/l and 59.92% in group II. No significant differences were observed in crude protein values of grown in control and group II ( < 0.05). Consequently, it was seen that commercial liquid organic fertilizers may be replaced by Zarrouk's medium except for nitrate, phosphate and bicarbonate in . cultures in order to decrease the production costs.Öğe Effect of light intensity on the pigment composition of Gracilaria verrucosa (Rhodophyta)(2012) Ak, Ilknur; Yücesan, MertIn this study, the influence of the light intensity on total chlorophyll, total carotenoids, phycocyanin, phycoerythrin and protein content of Gracilaria verrucosa (Hudson) Papenfuss were examined. Five different light intensities were arranged, e.g. 25 (group 1), 50 (group 2), 75 (group 3), 100 (group 4), and 150 (group 5) ?mol photons m-2 s-1. Maximum total chlorophyll (5.70±0.10 mg g-1 ww), phycoerythrin (5.39±0.44 mg g-1 ww) and phycocyanin (3.31±0.19 mg g-1 ww) contents were achieved in group 1 whereas the highest total carotenoids content was found in group 5 (1.62±0.04 mg g-1 ww). There was a statistically significant difference between the experimental groups (p< 0.05). A significant positive correlation was found between total chlorophyll and carotenoids content as well as total chlorophyll content and light intensities (p<0.05). It was found that total chlorophyll content was strongly correlated with phycocyanin and phycoerythrin contents (p<0.05). The phycobiliproteins (phycocyanin + phycoerythrin)/total chlorophyll ratio significantly increased when the light intensity decreased. The maximum protein content was determined in group 1 (24.19±0.28%), and statistically significant differences were determined among the groups (p< 0.05). Because G. verrucosa adapts different light regimes in a short time period, it is a potential candidate for Integrated Multitrophic Aquaculture (IMTA) systems, and it can be cultured at different water depths in these systems. © by PSP.Öğe EFFECT OF LIGHT INTENSITY ON THE PIGMENT COMPOSITION OF Gracilaria verrucosa (Rhodophyta)(Parlar Scientific Publications (P S P), 2012) Ak, Ilknur; Yucesan, MertIn this study, the influence of the light intensity on total chlorophyll, total carotenoids, phycocyanin, phycoerythrin and protein content of Gracilaria verrucosa (Hudson) Papenfuss were examined. Five different light intensities were arranged, e.g. 25 (group 1), 50 (group 2), 75 (group 3), 100 (group 4), and 150 (group 5) mu mol photons m(-2) s(-1). Maximum total chlorophyll (5.70 +/- 0.10 mg g(-1) ww), phycoerythrin (5.39 +/- 0.44 mg g(-1) ww) and phycocyanin (3.31 +/- 0.19 mg g(-1) ww) contents were achieved in group 1 whereas the highest total carotenoids content was found in group 5 (1.62 +/- 0.04 mg g(-1) ww). There was a statistically significant difference between the experimental groups (p<0.05). A significant positive correlation was found between total chlorophyll and carotenoids content as well as total chlorophyll content and light intensities (p<0.05). It was found that total chlorophyll content was strongly correlated with phycocyanin and phycoerythrin contents (p<0.05). The phycobiliproteins (phycocyanin + phycoerythrin)/total chlorophyll ratio significantly increased when the light intensity decreased. The maximum protein content was determined in group 1 (24.19 +/- 0.28 %), and statistically significant differences were determined among the groups (p<0.05). Because G. verrucosa adapts different light regimes in a short time period, it is a potential candidate for Integrated Multitrophic Aquaculture (IMTA) systems, and it can be cultured at different water depths in these systems.Öğe EFFECT OF SALINITY ON GROWTH CHARACTERISTICS AND PIGMENT COMPOSITION OF TWO STRAINS OF DUNALIELLA VIRIDIS TEODORESCO: LABORATORY AND OUTDOOR STUDIES(Parlar Scientific Publications (P S P), 2012) Ak, Ilknur; Cirik, Semra; Goksan, Tolga; Koru, EdisIn this study, the effect of salt concentration on growth characteristics and pigment accumulation of two strains of Dunaliella viridis Teodoresco (Ayvalik and Dalyan) which were cultured both at the laboratory and outdoor conditions were studied. The highest growth was found at 2M NaCl (1.33 +/- 0.12 d(-1)) for outdoor conditions. The highest cell numbers were observed at Ayvalik strain for both laboratory (8.06 +/- 0.40 x 10(6) cell ml(-1)) and outdoor conditions (5.83 +/- 0.19 x 10(6) cell ml(-1)). The minimum cell numbers determined at 3M NaCl cultures for laboratory experiments while it was found at 1M NaCl for outdoor cultures. It was measured that the cell volume of laboratory cultures (67.6 +/- 14.4 - 198.7 +/- 9.8 mu m(3)) were higher than outdoor cultures (48.7 +/- 9.7 - 110.5 +/- 4.9 mu m(3)). The total chlorophyll (a+b) and carotenoid contents were the highest at laboratory cultures for all salinity concentrations (p<0.05). The total chlorophyll and carotenoid concentration increased with salinity increase at outdoor conditions. In this study, growth rates, cell density and pigment content of two strains of D. viridis (Ayvalik and Dalyan) was determined and compared both under controlled laboratory and outdoor conditions with different salinity regimes. The results showed that the growth parameters and the pigment composition of D. viridis Ayvalik and Dalyan strains were strongly dependent on salinity.Öğe Effect of sodium acetate and sodium nitrate on biochemical composition of green algae Ulva rigida(Springer, 2015) Ak, Ilknur; Oztaskent, Cenk; Ozudogru, Yeliz; Goksan, TolgaIn this study, the effect of sodium acetate (C2H3NaO2) and sodium nitrate (NaNO3) concentrations on proximate and fatty acid composition of Ulva rigida (C. Agardh) was studied. Two trials were carried out. In the first experiment, the C2H3NaO2 was used as an organic carbon sources and five different concentrations of C2H3NaO2 were added; 0.25, 0.5, 1, 2, and 3 g/l. In the second trial, at the beginning of the experiment, 1 g/l C2H3NaO2 was added all groups, but the nitrogen regimes of the groups were changed. Five different nitrogen concentrations were used; 0.2 g/(l d), 0.3 g/(l d), 0.4 g/(l d), 0.6 g/(l d), and 0.11 g/(l d). According to our results, U. rigida cultivated with C2H3NaO2 and NaNO3 can successfully be used for both animal and human nutrition. The fatty acid methyl esters results showed that fatty acid contents of U. rigida were influenced by carbon (C2H3NaO2) and nitrogen (NaNO3) concentrations. The saturated fatty acids levels of U. rigida cultured in different NaNO3 concentrations were very high. The results indicated that C2H3NaO2 and NaNO3 addition during the culturing had considerable affects on proximate and fatty acid composition of the U. rigida. Using both C2H3NaO2 and NaNO3 offers a balanced fatty acid composition for both animal and human nutrition.Öğe Effects of light intensity, salinity and temperature on growth in Çamalti strain of Dunaliella viridis Teodoresco from Turkey(2008) Ak, Ilknur; Cirik, Semra; Göksan, TolgaIn this study, Dunaliella viridis was isolated from Çamalti salt work and its growth rate, cell density, chlorophyll-a and total carotenoids content were studied in a batch system. This strain was cultured at different NaCl concentrations (1, 2 and 3M), different temperatures (25 and 28°C) and different light intensities (50 and 75 ?mol photon/m2/sec). In this experiment maximum growth rate was at 2 M salinity with 28°C temperature and 50 ?mol photon/m2/sec light intensity. Maximum cell density for D. viridis was obtained at 25°C, 50 ?mol photon/m2/sec, 2M cultures. The highest chlorophyll-a and total carotenoids were calculated as 2.84±0.50 and 1.11±0.05 pg cell-1, respectively. The optimum temperature and salinity for growth of D. viridis strain were around 25°C and 2 M NaCl. The present study shows that cell densities and pigment yields of D. viridis Çamalti strain are strongly dependant on salinity, temperature and light intensity. © 2008 Asian Network for Scientific Information.Öğe Enhancement of antioxidant properties of Gongolaria barbata (Phaeophyceae) by optimization of combined light intensity and salinity stress(Taylor & Francis Ltd, 2022) Ak, Ilknur; Cankiriligil, Ekrem Cem; Turker, Gulen; Sever, Onur; Abomohra, AbdelfatahThe present study aimed to optimize the light intensity coupled with different salinity regimes for enhanced growth and antioxidant properties of the brown seaweed Gongolaria barbata. Five experimental trials (T-1-T-5) were suggested using response surface methodology, where growth rate and antioxidant properties of G. barbata were evaluated in each run at the end of the experiment. The model for growth rate showed differences not statistically significant among all studied groups. However, concentration of methanol extract needed to scavenge 50% of the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals (IC50), total phenolics, total flavonoids, total carotenoids, chlorophyll a and chlorophyll c showed significant differences among the five studied groups. Total phenolic and flavonoid contents were primarily affected by light, showing the highest values of 2.08 mg gallic acid equivalent g(-1) and 2.41 mg rutin g(-1) at 50 mu mol photon m(-2) s(-1). However, salinity stress showed a more pronounced impact on pigments. DPPH scavenging activity was influenced by the concentration of other compounds, which showed a significant increase by 34% in group T-4. The present study recommended light intensity of 53.86 mu mol photons m(-2) s(-1) at 24.02 parts per thousand salinity as the optimum conditions to achieve the maximum antioxidant activity along with phenolic and flavonoid contents (desirability = 0.82), without significant impact on the growth.Öğe GRACILARIA VERRUCOSA (HUDSON) PAPENFUSS CULTURE USING AN AGRICULTURAL ORGANIC FERTILIZER(Parlar Scientific Publications (P S P), 2011) Ak, Ilknur; Cetin, Zerrin; Cirik, Sukran; Goksan, TolgaIn this study, the effect of an agricultural organic fertilizer on growth, pigment, proximate and agar content of Gracilaria verrucosa (Hudson) Papenfuss was studied. The highest daily growth rate was determined in the agricultural organic fertilizer group as 4.0 % day(-1). Therefore, the growth of G. verrucosa with agricultural organic fertilizer and Conway's medium showed no significant differences (p>0.05). The maximum total chlorophyll content in the agricultural organic fertilizer was higher (20.7 +/- 1.5 mu g g(-1) than in Conway's medium (7.0 +/- 0.2 mu g g(-1)). The maximum protein (42.6 % dw) and lipid contents (7.6 +/- 0.1 % dw) were achieved in the agricultural organic fertilizer group. The significant differences were determined between the groups (p<0.05). The highest carbohydrate (58.1 +/- 0.4 % dw), ash (12.5 +/- 1.0 % dw) and agar (21.9 +/- 0.3 % dw) contents were found in Conway's medium. There was a statistically significant difference between the experimental groups (p<0.05). Consequently, it was seen that the agricultural organic fertilizer is suitable for G. verrucosa culture to produce human and animal food in order to decrease the production cost, but it is unsuitable for agar production.Öğe Gracilaria verrucosa (Hudson) papenfuss culture using an agricultural organic fertilizer(2011) Ak, Ilknur; Çetin, Zerrin; Cirik, Şükran; Göksan, TolgaIn this study, the effect of an agricultural organic fertilizer on growth, pigment, proximate and agar content of Gracilaria verrucosa (Hudson) Papenfuss was studied. The highest daily growth rate was determined in the agricultural organic fertilizer group as 4.0 % day -1. Therefore, the growth of G. verrucosa with agricultural organic fertilizer and Conway's medium showed no significant differences (p>0.05). The maximum total chlorophyll content in the agricultural organic fertilizer was higher (20.7±1.5 ?g g -1) than in Conway's medium (7.0±0.2 ?g g -1). The maximum protein (42.6 % dw) and lipid contents (7.6±0.1 % dw) were achieved in the agricultural organic fertilizer group. The significant differences were determined between the groups (p<0.05). The highest carbohydrate (58.1 ±0.4 % dw), ash (12.5&plusum;1.0 % dw) and agar (21.9±0.3 % dw) contents were found in Conway's medium. There was a statistically significant difference between the experimental groups (p<0.05). Consequently, it was seen that the agricultural organic fertilizer is suitable for G. verrucosa culture to produce human and animal food in order to decrease the production cost, but it is unsuitable for agar production. © by PSP.Öğe Gracilaria verrucosa (Hudson) papenfuss production in intensive fish culture(Ege Univ, 2006) Turan, Gamze; Ak, Ilknur; Cirik, Semra; Koru, Edis; Basaran, Ash KaymakciIn this study, five different culture techniques of a red macro algae Gracilaria verrucosa (Hudson) Papenfuss at a commercial marine fish farm located in Sigacik Bay (Seferihisar, Izmir) were examined. The experiment was performed between 01 April 2002 and 01 January 2002. Known five different culture techniques of G. verrucosa were applied at the fish cages. These are culturing the algae at bottom by tying the thalli to the natural substratums, culturing the algae at the bottom in different mesh-size net-bags, culturing the algae on the ropes near the fish cages, culturing the algae on the ropes in the fish cages and culturing the algae in the net-bags near the fish cages. During the study biomass values and water quality parameters were measured and recorded. From the result of this study, the best culture technique was determined as culturing the algae in the net-bags near the fish cages. The highest spesific growth rate (5.8%/day) in November and December and the lowest spesific growth rate (-9.9%/day) in July were calculated.Öğe Greenhouse Cultivation of Gracilaria verrucosa (Hudson) Papenfuss and Determination of Chemical Composition(Central Fisheries Research Inst, 2010) Cirik, Sukran; Cetin, Zerrin; Ak, Ilknur; Cirik, Semra; Goksan, TolgaThe agarophyte Gracilaria verrucosa (Hudson) Papenfuss was cultivated under greenhouse conditions in Modified Johnson Medium over a 5-month period. Biomass productivity ranged between 5.00 g L-1 to 16.37 g L-1 and the highest biomass was obtained in December. Relative growth rate (RGR) varied from 4.03 +/- 1.63 to 1.21 +/- 0.34% day(-1). While the highest percentages of protein were found in December (20.28 +/- 0.94% of dw), the lowest percentages were in March (14.99 +/- 0.14% of dw). Phosphorus content ranged from 101.66 +/- 3.11 ppm (march) to 114.03 +/- 5.44 ppm (december). The lipid concentrations of G. verrucosa were measured within 2.39 +/- 0.77% dw and 2.66 +/- 0.94% dw. The agar yiel were determined between 9.65 +/- 1.12 and 18.64 +/- 2.38% of dw in december and march. The melting and gelling temperatures were stable through the experiment. The highest and the lowest values for both melting and gelling temperatures were 39.00 +/- 0.35 degrees C (december) - 34.00 +/- 0.32 degrees C (march) and 86.50 +/- 0.30 degrees C (march) - 85.50 +/- 040 degrees C (february), respectively. As a result of this study G. verrucosa could be cultivated in greenhouse conditions succesfully. Depending on the high growth rates, high concentrations of crude protein, phosphorus and agar of Gracilaria we conclude that it can be cultivated in greenhouse conditions.Öğe Growth Characteristics of the Alga Haematococcus pluvialis Flotow as Affected by Nitrogen Source, Vitamin, Light and Aeration(Central Fisheries Research Inst, 2011) Goksan, Tolga; Ak, Ilknur; Kilic, CenkerIn the present study, the effects of various inorganic nitrogen sources, light intensities, aeration rates and especially vitamins were investigated in vegetative Haematococcus pluvialis Flotow cultures. The best growth among the nitrogen sources was achieved in NaNO(3) (1.0 g/L) and KNO(3) (0.5 g/L) with cell densities of 25.3 and 26.3x10(4) cells/ml respectively. In vitamin trials, the highest cell numbers were found in 0.1(0.3 mu M), 1.0 (4 mu M) and 0.1 ing/L (0.75 mu M) concentrations for thiamin, biotin and B12 respectively. It was also seen that the use of thiamin alone was sufficient instead of using the vitamin mix. Cell growth was significantly higher in 75 and 150 mu mol photon m(-2) s(-1) illuminations compared to 20 and 40 mu mol photon m(-2) s(-1). As for aeration, optimum airflow rate was 1.0 lpm, while supra-optimum levels ceased the growth, cell diameter and pigment content increased. So, it may play a role as a secondary stress factor on H. pluvialis cells in reddening stage.Öğe Growth of Brachionus plicatilis (Rotifer) on various diets(Ege Univ, 2006) Ozbas, Bircan; Goksan, Tolga; Ak, IlknurIn this study, in which the effects of various food sources on the rotifer Brachionus plicatilis were examined, rotifers were fed with Nannochloropsis sp., yeast (Saccharomyces cerevisiae) and dried Spirulina meal. In the first trial, optimum Spirulina concentration was found to be 0.01 g / 10(6) rotifers per day. In the experimental groups, 5 groups were arranged, e.g., alga, alga+yeast, alga+Spirulina, yeast+Spirulina and yeast/2+Spirulina. In the microscopic observations, it was seen that Spirulina particles were larger than that rotifer can consume. Consequently, the groups that contained alga showed the best growth pattern. Spirulina could not be consumed due to the larger particle size. Regarding the yeast cells, although their size are in the optimum range for rotifer feeding, they exhibited a lower growth rate compared to the groups fed with alga due to the fact that the yeast caused the culture medium to deteriorate.Öğe Health Risk Assessment and Mineral Contents in Brown Seaweed Colpomenia sinuosa for Human Consumption(Springer Int Publ Ag, 2024) Turker, Gulen; Ak, Ilknur; Tas, Elif CagriThis study focuses on the mineral content and health risk assessment of the brown seaweed Colpomenia sinuosa. The mineral composition of the seaweed samples (Na, K, Mg, Fe, Cu, Zn, Mn, P, Ni, Pb, Cd, Cr, Al) was investigated from three different Turkish coastal locations: & Idot;zmir Bay (S1), the Strait of & Ccedil;anakkale (S2), and the Sea of Marmara (S3). The mineral contents of samples were analyzed using Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES) as part of our methodology. It was found that the mineral content varied significantly depending on the location from which the samples were taken. The highest levels of Na, Ca, Mg, Fe, Ni, and Mn were observed in the samples from & Idot;zmir Bay, whereas those from the Sea of Marmara showed elevated levels of P and Zn. The study also revealed the presence of heavy metals, including Pb, Co, Cd, Cr, and Al, in the seaweed. According to hazard index (HI) calculations, adult consumption of this seaweed poses a low health risk, with a hazard index below 1. Various heavy metals have been detected in the seaweed, but their concentrations are not high enough to pose significant health risks, and therefore, the seaweed is safe for human consumption within reasonable limits. Our results suggest that C. sinuosa could be a valuable source of essential minerals for human consumption.Öğe Heavy metals uptake from aqueous solutions using marine algae (Colpomenia sinuosa): kinetics and isotherms(Taylor & Francis Ltd, 2012) Cirik, Yeliz; Bekci, Zehra Molu; Buyukates, Yesim; Ak, Ilknur; Merdivan, MelekThe adsorption of copper, zinc, cobalt, lead and cadmium ions onto Colpomenia sinuosa was studied as a function of contact time, initial metal ion concentration and initial pH. In addition, desorption studies were performed. Characterisation of this adsorbent was also confirmed by Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM) analysis. Batch adsorption experimental data were analysed using Langmuir, Freundlich and Dubinin-Raduschkevich (D-R) adsorption isotherms. The results indicated that the biosorption equilibrium was well described by both the Freudlich and D-R isotherms. Moreover, sorption kinetics was performed and it was observed that equilibrium was reached in <60 min, which could be described by the pseudo-second-order kinetic model for all heavy metals. The sorption of heavy metals onto the biomass was largely dependent on the initial solution pH. The elution efficiency for heavy metal ions desorption from C. sinuosa was determined for 0.1 M HCl, 1.0 M HCl and 1.0 M HNO3. Desorption efficiency and also adsorption capacity were highest for Pb(II). The results indicate that C. sinuosa has great potential for the removal of heavy metals in an ecofriendly process.Öğe Impact of UV-C radiation on growth of micro and macro algae in irrigation systems(Elsevier Science Bv, 2019) Tekiner, Murat; Ak, Ilknur; Kurt, MustafaSustainability of irrigation systems is crucially important for both economical and efficient usage of natural water sources. Irrigation system efficiency could be negatively affected by some natural flora such as micro (Arthrospira maxima) and macro (Cladophora sp.) algae. In this study, efficiency of UV-C radiation, which has been proven effectiveness in demolishing of bacteria and microbes in medicine, for micro and macro algae. Our study was performed under laboratory conditions and was carried out in two main phases. In the first phase, spectral absorbance curves were established for micro and macro algae, the greatest absorbance value was determined in UV region (300 nm to 450 nm). In the second phase, to analyze the growth of algae species depending on UV-C illumination, micro algae within three different basins with the same cross-sectional area and different water depths (D1 :12.5 cm, D2:25 cm, D3:45cm) were exposed to UV-C radiation for different durations (2, 4, 6. 8 and 16 s). The maximum inhibition on the growth rate of A. maxima was observed in 16 s UV-C radiation treatment groups of D1 and D2 basins. Since Cladophora sp. macro algae are aquatic weeds floating over the water surface, they were exposed to UV-C radiation similar to micro algae only in D1 basin. The greatest reduction rate in biomass values of Cladophora sp. was observed in 16 s UV-C exposed groups. The experimental findings showed that UV-C radiation could be used to reduce growth of micro and macro algae. It was concluded based on present findings that UV-C radiation could reliably be used for efficient water use in open or dosed irrigation systems. (C) 2019 Elsevier B.V. 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