Person: TOKSOY ÖNER, EBRU
Loading...
Email Address
Birth Date
Research Projects
Organizational Units
Job Title
Last Name
TOKSOY ÖNER
First Name
EBRU
Name
4 results
Search Results
Now showing 1 - 4 of 4
Publication Metadata only From healing wounds to resorbable electronics, levan can fill bioadhesive roles in scores of markets(IOP PUBLISHING LTD, 2019) TOKSOY ÖNER, EBRU; Combie, Joan; Oner, Ebru ToksoyLevan is a fructose homopolysaccharide which gained attention recently for its unusual combination of properties distinguishing it from other natural biodegradable polysaccharides like chitosan, cellulose or starch. Among the strongest bioadhesives, film-forming levan is garnering interest for its role in some simple solutions to difficult problems. One of these is illustrated by the elegant research using laser-based techniques to construct levan films for healing wounds and burned tissue. Another is the development of bioresorbable electronic implants. Levan has been found in habitats as diverse as salterns and thermal waters to tropical plants and sugar factories. This review of the low viscosity, levan adhesive describes the mechanisms by which it forms bonds and the reasons behind some of its practical and industrial applications. Here we present descriptions from the literature for feasible approaches ready to transition from the laboratory to those searching for answers in fields as varied as medicine, packaging and furniture assembly.Publication Metadata only Levan based fibrous scaffolds electrospun via co-axial and single-needle techniques for tissue engineering applications(ELSEVIER SCI LTD, 2018) TOKSOY ÖNER, EBRU; Avsar, Gulben; Agirbasli, Deniz; Agirbasli, Mehmet Ali; Gunduz, Oguzhan; Oner, Ebru ToksoyThis represents the first systematic study where levan polysaccharide was used to fabricate fibrous matrices by co-axial and single-needle electrospinning techniques. For this, hydrolyzed (hHL) and sulfated hydrolyzed (ShHL) Halomonas levan were chemically synthesized and used together with polycaprolactone (PCL) and polyethyleneoxide (PEO) for the spinning process. In co-axially spun matrices, ultimate tensile strength (UTS) were found to increase with increasing ShHL concentration and elongation at break of PCL + ShHL matrices increased up to ten-fold when compared to PCL matrices. Similarly, in single-needle spun matrices, higher elongation at break values were obtained by blending HL and ShHL with PEO pointing to the effective energy absorbing features. Dense and fine fibers were characterized by FTIR and SEM. Cell viability and fluorescence imaging of L929 fibroblasts and HUVECs as well as heparin mimetic activity of the matrices pointed to their high potential to be used in decreasing neointimal proliferation and thrombogenicity of grafts and prosthesis.Publication Metadata only Halomonas smyrnensis as a cell factory for co-production of PHB and levan(ELSEVIER SCIENCE BV, 2018) KASAVİ, CEYDA; Tohme, Souha; Haciosmanoglu, Gul Gulenay; Eroglu, Mehmet Sayip; Kasavi, Ceyda; Genc, Seval; Can, Zehra Semra; Oner, Ebru ToksoyLevan is a fructan type polysaccharide that has long been considered as an industrially important biopolymer however its limited availability is mainly due to the bottlenecks associated with its large-scale production. To overcome such bottlenecks in the commercialization of this very promising polysaccharide, co-production of levan with polyhydroxyalkanoates (PHAs) by halophilic Halomonas smyrnensis cultures has been proposed in this study for the first time. After in silico and in vitro assessment of PHA accumulation, fermentation profiles for levan and PHA concentrations were obtained in the presence of sucrose and glucose and the PHA granules observed by TEM were found to be poly(3-hydroxybutyrate) (PHB) after detailed structural characterization by GC-MS, DSC, FTIR and NMR. Six nutrient limitation strategies based on nitrogen (N) and phosphorus (P) were tested but highest levan and PHB yields were obtained under unlimited conditions. H. smyrnensis is proved to co-produce PHB and levan while using inexpensive carbon sources which is a commercially successful microbial cell factory system showing a great potential in lowering manufacturing costs and aiming for a zero waste policy within the biorefinery concept. (C) 2018 Elsevier B.V. All rights reserved.Publication Metadata only Development of a cost-effective production process for Halomonas levan(SPRINGER, 2018) TOKSOY ÖNER, EBRU; Erkorkmaz, Burak Adnan; Kirtel, Onur; Duru, Ozlem Ates; Oner, Ebru ToksoyLevan polysaccharide is an industrially important natural polymer with unique properties and diverse high-value applications. However, current bottlenecks associated with its large-scale production need to be overcome by innovative approaches leading to economically viable processes. Besides many mesophilic levan producers, halophilic Halomonas smyrnensis cultures hold distinctive industrial potential and, for the first time with this study, the advantage of halophilicity is used and conditions for non-sterile levan production were optimized. Levan productivity of Halomonas cultures in medium containing industrial sucrose from sugar beet and food industry by-product syrup, a total of ten sea, lake and rock salt samples from four natural salterns, as well as three different industrial-grade boron compounds were compared and the most suitable low-cost substitutes for sucrose, salt and boron were specified. Then, the effects of pH control, non-sterile conditions and different bioreactor modes (batch and fed-batch) were investigated. The development of a cost-effective production process was achieved with the highest yield (18.06 g/L) reported so far on this microbial system, as well as the highest theoretical bioconversion efficiency ever reported for levan-producing suspension cultures. Structural integrity and biocompatibility of the final product were also verified in vitro.