Browsing by Subject "Isolation and purification"
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Item Open Access Bacteria immobilized electrospun polycaprolactone and polylactic acid fibrous webs for remediation of textile dyes in water(Elsevier, 2017-10) Sarioglu O.F.; S. Keskin, N. O.; Celebioglu A.; Tekinay, T.; Uyar, TamerIn this study, preparation and application of novel biocomposite materials for textile dye removal which are produced by immobilization of specific bacteria onto electrospun nanofibrous webs are presented. A textile dye remediating bacterial isolate, Clavibacter michiganensis, was selected for bacterial immobilization, a commercial reactive textile dye, Setazol Blue BRF-X, was selected as the target contaminant, and electrospun polycaprolactone (PCL) and polylactic acid (PLA) nanofibrous polymeric webs were selected for bacterial integration. Bacterial adhesion onto nanofibrous webs was monitored by scanning electron microscopy (SEM) imaging and optical density (OD) measurements were performed for the detached bacteria. After achieving sufficient amounts of immobilized bacteria on electrospun nanofibrous webs, equivalent web samples were utilized for testing the dye removal capabilities. Both bacteria/PCL and bacteria/PLA webs have shown efficient remediation of Setazol Blue BRF-X dye within 48 h at each tested concentration (50, 100 and 200 mg/L), and their removal performances were very similar to the free-bacteria cells. The bacteria immobilized webs were then tested for five times of reuse at an initial dye concentration of 100 mg/L, and found as potentially reusable with higher bacterial immobilization and faster dye removal capacities at the end of the test. Overall, these findings suggest that electrospun nanofibrous webs are available platforms for bacterial integration and the bacteria immobilized webs can be used as starting inocula for use in remediation of textile dyes in wastewater systems.Item Open Access Cyclodextrin-functionalized mesostructured silica nanoparticles for removal of polycyclic aromatic hydrocarbons(Academic Press Inc., 2017) Topuz, F.; Uyar, T.Polycyclic aromatic hydrocarbons (PAHs) are the byproducts of the incomplete combustion of carbon-based fuels, and have high affinity towards DNA strands, ultimately exerting their carcinogenic effects. They are ubiquitous environmental contaminants, and can accumulate on tissues due to their lipophilic nature. In this article, we describe a novel concept for PAH removal from aqueous solutions using cyclodextrin-functionalized mesostructured silica nanoparticles (CDMSNs) and pristine mesostructured silica nanoparticles (MSNs). The adsorption applications of MSNs are greatly restricted due to the absence of surface functional groups on such particles. In this regard, cyclodextrins can serve as ideal functional molecules with their toroidal, cone-type structure, capable of inclusion-complex formation with many hydrophobic molecules, including genotoxic PAHs. The CDMSNs were synthesized by the surfactant-templated, NaOH-catalyzed condensation reactions of tetraethyl orthosilicate (TEOS) in the presence of two different types of cyclodextrin (i.e. hydroxypropyl-β-cyclodextrin (HP-β-CD) and native β-cyclodextrin (β-CD)). The physical incorporation of CD moieties was supported by XPS, FT-IR, NMR, TGA and solid-state 13C NMR. The CDMSNs were treated with aqueous solutions of five different PAHs (e.g. pyrene, anthracene, phenanthrene, fluorene and fluoranthene). The functionalization of MSNs with cyclodextrin moieties significantly boosted the sorption capacity (q) of the MSNs up to ∼2-fold, and the q ranged between 0.3 and 1.65 mg per gram CDMSNs, of which the performance was comparable to that of the activated carbon.Item Open Access Molecular entrapment of volatile organic compounds (VOCs) by electrospun cyclodextrin nanofibers(Elsevier, 2016-02) Celebioglu A.; Sen, H. S.; Durgun, Engin; Uyar, TamerIn this paper, we reported the molecular entrapment performance of hydroxypropyl-beta-cyclodextrin (HPβCD) and hydroxypropyl-gamma-cyclodextrin (HPγCD) electrospun nanofibers (NF) for two common volatile organic compounds (VOCs); aniline and benzene. The encapsulation efficiency of CD samples were investigated depending on the various factors such as; CD form (NF and powder), electrospinning solvent (DMF and water), CD (HPβCD and HPγCD) and VOCs (aniline and benzene) types. BET analysis indicated that, electrospun CD NF have higher surface area compared to their powder form. In addition DMA measurement provided information about the mechanical properties of CD NF. The encapsulation capability of CD NF and CD powder was investigated by 1H-NMR and HPLC techniques. The observed results suggested that, CD NF can entrap higher amount of VOCs from surroundings compared to their powder forms. Besides, molecular entrapment efficiency of CD NF also depends on CD, solvent and VOCs types. The inclusion complexation between CD and VOCs was determined by using TGA technique, from the higher decomposition temperature of VOCs. Finally, our results were fortified by the modeling studies which indicated the complexation efficiency variations between CD and VOC types. Here, the inclusion complexation ability of CD molecules was combined with very high surface area and versatile features of CD NF. So these findings revealed that, electrospun CD NF can serve as useful filtering material for air filtration purposes due to their molecular entrapment capability of VOCs.Item Open Access Surface-modified bacterial nanofibrillar PHB scaffolds for bladder tissue repair(Taylor and Francis Ltd., 2016) Karahaliloǧlu, Z.; Demirbilek, M.; Şam, M.; Saǧlam, N.; Mizrak, A. K.; Denkbaş, E. B.The aim of the study is in vitro investigation of the feasibility of surface-modified bacterial nanofibrous poly [(R)-3-hydroxybutyrate] (PHB) graft for bladder reconstruction. In this study, the surface of electrospun bacterial PHB was modified with PEG- or EDA via radio frequency glow discharge method. After plasma modification, contact angle of EDA-modified PHB scaffolds decreased from 110 � 1.50 to 23 � 0.5 degree. Interestingly, less calcium oxalate stone deposition was observed on modified PHB scaffolds compared to that of non-modified group. Results of this study show that surface-modified scaffolds not only inhibited calcium oxalate growth but also enhanced the uroepithelial cell viability and proliferation.