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    Biosorption of lead(II) and copper(II) metal ions on Cladophora glomerata (L.) kutz. (Chlorophyta) algae: Effect of algal surface modification
    (Slovensko Kemijsko Drustvo, 2008) Yalcin, Emine; Cavusoglu, Kueltigin; Maras, Meltem; Biyikoglu, Mutluhan
    Heavy metals are present in some industrial effluents, being responsible for environmental pollution. Biosorption of heavy metals can be an effective method for the removal of heavy metal ions from wastewaters. In this study Pb(II) and Cu(II) biosorption by Cladophora glomerata algae was investigated in batch system from a binary mixture. The effects of some important parameters such as pH, initial concentration of heavy metals and modification of algae surface by heat/acid treatment on biosorption capacity was studied. The maximum biosorption capacity of Cladophora glomerata was 15.0mg/g at pH 5.0 for Cu( II) and 22.5 mg/g at pH 4.0 for Pb( II) metal ions. The biosorption capacity of Pb( II) and Cu( II) ions on the acid/heat-treated biomass was increased as 1.38 and 1.45 times than untreated form, respectively. The biosorption of Pb ( II) and Cu ( II) heavy metal ions on Cladophora glomerata appears to be an efficient and low cost alternative to be considered in industrial wastewater treatment.
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    Effects of cypermethrin on Allium cepa
    (Wiley, 2012) Cavusoglu, Kultigin; Kaya, Arzu; Yilmaz, Fadime; Yalcin, Emine
    In this study, toxic effects of the cypermethrin in Allium cepa L. cells were investigated. For this aim, we investigated the changes in pigment contents, antioxidant enzymes, mitotic index and chromosomal abnormalities as indicators of toxicity. The seeds were treated with different doses (1.5, 3.0, 6.0 ppm) of cypermethrin for 72 h. The result showed that there was a significant alteration in the tested parameters depending on treatment dose in the seeds exposed to cypermethrin when compared to the control group. Cypermethrin exposure significantly reduced the carotenoid, chlorophyll a and b pigments in all treatment groups. The activity of superoxide dismutase showed a concentration-time dependent increase and the maximum increase was observed on day 15 of treatment at 6.0 ppm cypermethrin exposure. The activity of catalase increased gradually with increasing cypermethrin concentration, but a soft decrease in CAT activity was decreased after 15 days of 1.5 ppm and 3.0 ppm cypermethrin treatment. In the roots treated with 1.5, 3.0, and 6.0 ppm cypermethrin, the level of malondialdehyde was about 1.8, 2.4, and 3.4 times higher than the control group, respectively. It was also found that cypermethrin has a mitodepressive action on mitosis, and the MI was decreased depending on the dose of cyprmethrin. All of the concentrations of cypermethrin induced chromosomal abnormalities and the most common abnormality observed in the present study was chromosome bridges. (c) 2011 Wiley Periodicals, Inc. Environ Toxicol 2012.
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    Preliminary characterization of biosurfactants produced by microorganisms isolated from refinery wastewaters
    (Taylor & Francis Ltd, 2010) Yalcin, Emine; Ergene, Aysun
    Some bacterial strains isolated from refinery wastewaters were identified as Pseudomonas aeruginosa RWI, Pseudomonas putida RWII, Pseudomonas fluorescens RWIII and Burkholderia cepacia RWIV, and the biosurfactants produced by these strains were coded as BS-I, BS-II, BS-III and BS-IV, respectively. The bacterial strains were characterized by the following biochemical methods: Gram stain, oxidase activity, indol, lactose and growth at 42 degrees C. Biosurfactant production was evaluated by: emulsification activity, surface tension measurement and critical micelle concentration. Chemical characterization of the biosurfactants was done by: FTIR and analysis of carbohydrate, protein and lipid content. The biosurfactants showed good emulsification activity against different hydrocarbon sources. The initial surface tension of culture broth was determined as 67.3 mN/m, and production of BS-I, BS-II, BS-III and BS-IV lowered this value to 35.9, 49.2, 51.6 and 45.7 mN/m, respectively. The critical micelle concentration of the biosurfactants was found to be in the range 10-50 mg/L. From the results of this study it was observed that the refinery wastewaters are a suitable source for isolation of biosurfactant-producing bacteria, but are not a substrate for biosurfactant production.