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    Anoxybacillus flavithermus loaded y-Fe2O3 magnetic nanoparticles as an efficient magnetic sorbent for the preconcentrations of Cu(II) and Mn(II)
    (Pergamon-Elsevier Science Ltd, 2022) Ozdemir, Sadin; Turkan, Zeynep; Kilinc, Ersin; Altuner, Elif Esra; Sen, Fatih
    It was hypothesized that-iron( oxide nanoparticles (y-Fe2O3 NPs) functionalized with Anoxybacillus flavithermus (A. flavithermus) as an effective magnetic sorbent for the preconcentrations of toxic metal ions. It is clear to conclude that the main novelty of this study is that y-Fe2O3 NPs loaded with A. flavithermus is selective-specific for Cu(II), Mn(II). Structural functional groups of the samples were elucidated by FTIR, and SEM. Significant experimental parameters were investigated in detail. 0.2 mL min(-1) of flow rate, 5 mL of 1 M of hydrochloric acid as eluent, 150 mg biogenic mass sample, and 150 mg y-Fe2O3 NPs for supporting material were found as the best conditions. This developed method has been tested and verified using certified and standard reference materials. As a result of the studies, the pre-concentration factor of the Cu(II), Mn(II) metals was calculated as 40. All measurements showed that the developed solid-phase extraction (SPE) columns are available for 32 cycles. The use of y-Fe2O3 NPs equipped with A. flavithermus as an effective magnetic sorbent for the first measurements of ions was thoroughly studied. In order of the biosorption capacities were calculated as 26.0, and 30.3 mg/g for Cu (II), Mn(II), respectively. The developed method for specifying the samples showed excellent to excellent results.
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    A new magnetized thermophilic bacteria to preconcentrate uranium and thorium from environmental samples through magnetic solid-phase extraction
    (Elsevier, 2020) Ozdemir, Sadin; Kilinc, Ersin; Yalcin, Mustafa Serkan; Soylak, Mustafa; Sen, Fatih
    A magnetic solid-phase extraction (MSPE) method was developed for simultaneous preconcentrations of U(VI) and Th(IV) before their measurements by inductively coupled plasma optical emission spectrometry (ICP-OES). The main idea of this biotechnological application depends on the use of bacteria, thermophilic Bacillus cereus SO-14, as a solid-phase biosorbent. It was immobilized to gamma-Fe2O3 magnetic nanoparticles and used for MSPE. Characterization of the biosorbent was performed using the scanning electron microscope (SEM), the energy dispersive X-ray (EDX) and Fourier transform infrared (FT-IR) spectroscopy. Also, the the best conditions of experimental parameters were examined, and the reliability of the method developed was verified by applying the certified reference materials. Limit of detections (LODs) of the U(VI) and Th(IV) was calculated as 0.008 and 0.013 ng mL(-1) respectively. Relative standard deviations (RSDs) were found to be 1.6 and 2.4 %, respectively, for U(VI) and Th(IV). R-2 was also calculated as 0.9991. Preconcentration factors were achieved as 100 for both elements. It should be highlighted that LODs were critically improved and the sensitivity of ICP-OES was enhanced. (C) 2020 Elsevier B.V. All rights reserved.
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    Preconcentrations of Cu (II) and Mn (II) by magnetic solid-phase extraction on Bacillus cereus loaded gamma-Fe2O3 nanomaterials
    (Academic Press INC Elsevier Science, 2022) Özdemir, Sadin; Türkan, Zeynep; Kılınç, Ersin; Bayat, Ramazan; Soylak, Mustafa; Sen, Fatih
    For the simultaneous preconcentrations of Cu(II) and Mn(II), a novel preconcentration technique was developed and described. Bacillus cereus loaded magnetic gamma-Fe2O3 nanoparticles were prepared and used as support materials on solid-phase extraction procedure. Important experimental parameters were investigated in details and pH 6.0, 3 mL min(-1) of flow rate, 5 mL of 1 mol L-1 of HCl as eluent, 200 mg of biomass, and 200 mg of magnetic gamma-Fe2O3 nanoparticles as support material was found as the best conditions. The preconcentrations factor were found to be 80 for Cu (II) and Mn(II). It was confirmed by the results that SPE columns could be used in 32 cycles. The LOD values calculated for Cu (II) and Mn (II) were 0.09 and 0.08 ng mL(-1), respectively. The RSD values found were less than 3.4%. The extraction recoveries were achieved as higher than 98%. The biosorption capacities of Cu (II), and Mn (II) were 26.0 mg g(-1), 30.3 mg g(-1) respectively. The approach devised for analyzing analyte concentrations in food samples proved to be successful.
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    Purification and characterization of thermostable a-amylase produced from Bacillus licheniformis So-B3 and its potential in hydrolyzing raw starch
    (Pergamon-Elsevier Science Ltd, 2021) Fincan, Sema Aguloglu; Ozdemir, Sadin; Karakaya, Adem; Enez, Baris; Mustafov, Sibel Demiroglu; Ulutas, Mehmet Sefa; Sen, Fatih
    Aims: This work was achieved to obtain the optimum culture conditions of the thermostable alpha-amylase produced by thermophilic Bacillus licheniformis SO-B3. Furthermore, the alpha-amylase was purified and then characterized, and also its kinetic parameters were determined. Materials and methods: A new thermotolerant bacteria called Bacillus licheniformis SO-B3 employed in this work was isolated from a sample of thermal spring mud in Sirnak (Meyremderesi). Several parameters such as the impact of temperature, time, and pH on enzyme production were examined. Thin-Layer Chromatography (TLC) was employed to analyze the end-products of soluble starch hydrolysis, and the utilization of purified alpha-amylase in the clarification of unripe apple juices was studied. Key findings: The highest enzyme production conditions were determined as 35 degrees C, 36th hour, and pH 7.0. Thermostable alpha-amylase was purified by 70% ammonium sulfate precipitation, DEAE-cellulose ion-exchange chromatography, and dialysis, with a 51-purification fold and 30% yield recovery. The K-m and V-max values for this enzyme were 0.004 mM and 3.07 mu mol min(-1) at 70 degrees C, respectively. The alpha-amylase's molecular weight was found as 74 kDa. In addition, alpha-amylase showed a good degradation rate for raw starch. Significance: It was hypothesized that Bacillus licheniformis SO-B3 could be used as an alpha-amylase source. These findings displayed that purified enzyme could be utilized in fruit juice industries for clarification of apple juice and raw starch hydrolyzing.
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    Resistance, removal, and bioaccumulation of Ni (II) and Co (II) and their impacts on antioxidant enzymes of Anoxybacillus mongoliensis
    (Elsevier Science Inc, 2020) Akkoyun, Mahire Bayramoglu; Ozdemir, Sadin; Kilinc, Ersin; Birhanli, Emre; Aygun, Aysenur; Sen, Fatih
    In this study, it was hypothesis that A. mongoliensis could be used as bioindicator for Ni (II) and Co (II). Thus, Ni (II) and Co (II) resistance, removal, bioaccumulation, and the impacts of them on antioxidant enzyme systems of thermophilic Anoxybacillus mongoliensis were investigated in details. The bioaccumulation of Ni (II) and Co (II) on the cell membrane of thermophilic A. mongoliensis, variations on surface macrostructure and functionality by FT-IR and SEM, and determination of antioxidant enzyme activities were also tested. The highest bioaccumulation values of Co (II) and Ni (II) were detected as 102.0 mg metal/g of dry bacteria at 10 mg/L for the 12th h and 90.4 mg metal/g of dry bacteria for the 24th h, respectively, and the highest Ni (II) and Co (II) cell membrane bioaccumulation capacities of A. mongoliensis were determined as 268.5 and 274.9 mg metal/g wet membrane, respectively at the 24th h. In addition, increasing on SOD and CAT activities were observed on depend of concentration of Ni (II) and Co (II) with respect to control. The antioxidant enzyme activity results also indicated that A. mongoliensis might be used as a bioindicator for Ni (II) and Co (II) pollution in environmental water specimens.