Sürdürülebilir Kalkınma Amaçları
Yazarlar
- Dertli, Enes(47)
- Pat, Suat(29)
- Özen, Soner(29)
- Şenay, Volkan(24)
- Korkmaz, Şadan(23)
- Esmer, Yusuf(21)
- Şahin, Engin(21)
- Korkmaz, Özge(20)
- Cuce, Erdem(19)
- Öner, Erdal(18)
- Öztürk, Mesut(18)
- Artar, Musa(17)
- Yilmaz, Mustafa Tahsin(17)
- İspirli, Hümeyra(16)
- Ecem Bayram, Nesrin(15)
- Kaya, Yunus(15)
- Cinar, Mehmet(13)
- Cuce, Pinar Mert(12)
- Kamiloğlu, Aybike(12)
- Kutlu, Naciye(12)
- Mercan, Emin(12)
- Birinci, Ahmet(11)
- Bulut, Mehmet(11)
- Yaylacı, Murat(11)
- Bayram, Ozkan(10)
- Can, Zehra(10)
- Doğan, Zeki(10)
- Kahya, Cem(10)
- Karaali, Rabi(10)
- Pabuçcu, Hakan(10)
- Tosun, Figen Çam(10)
- Özdemir, Akın(10)
- Ayazoglu, Rabil(9)
- Battal, Fetullah(9)
- Bayram, Nesrin Ecem(9)
- Büte, Mustafa(9)
- Ertugrul, Mehmet(9)
- Kadakal, Mahir(9)
- Kaplan, Abdullah(9)
- Sarikaya, İsmail(9)
Yayınlar
- MakaleYalnız künye2021MORPHOMETRIC ANALYSIS TO INFER HYDROLOGICAL BEHAVIOUR OF CORUH RIVER BASIN (NORTHERN TURKEY) USING GIS TECHNIQUE
Yildirim, Umit
Morphometric analysis is a very practical approach for evaluating hydrological processes for watersheds. The combination of morphometric, geological, and geomorphological characteristics of the river basin helps to gain further insights in forecasting hydrological phenomena (such as flooding, soil erosion, and groundwater potential). In this study, the morphometric analysis of the Coruh River Basin was conducted using GIS to establish effective water management. Firstly, the basic morphometric parameters (basin area, basin length, basin perimeter, stream order, stream number, and total stream length) were calculated for both CRB and its subbasins. Then, characteristic morphometric parameters (drainage density, drainage texture, form factor, length of the overland flow, topographic wetness index, and stream power index) were determined. Results showed that the infiltration capacity of the subsurface material was low, and the surface runoff was slow in the subbasins located close to the CRB's outlet. Therefore, these subbasins are more sensitive to flooding, erosion, and landslides compared to others. Soil erosion and thus sediment loss is higher in 1st, 2nd, 3rd, and 5th subbasins, and the groundwater potential is higher in headwater areas of the basin. This study revealed that the GIS-based morphometric analysis is beneficial to implement water management tool at the watershed scale.
AtıfWoS1
İncele - MakaleYalnız künye2021Scopus SJRQ2An online software to simulate the shielding properties of materials for neutrons and photons: NGCal
Gökçe, H. S.; Güngör, O.; Yilmaz, H.
NGCal, a free online computation software (http://ngcal.com), has been developed for narrow beam transmission properties of photons (for energies of X rays and gamma rays between 0.002 MeV and 20 MeV), thermal (25.4 meV) and fast neutrons (4 MeV), in this regard it theoretically calculates the mass and linear attenuation coefficient/factor, mean free path, half- and tenth-value layers of materials formed by elements, compounds and composites. Its calculation assumptions, user guide as well as a comparative example of its results to those of other online computation platforms (XCOM, NCNR, WinXCOM, MCNPX, and Phy-X/PSD) are presented in this study. The developed software allows for more data input consisting of elements/oxides/compound and their fractions, and presents a number of shielding results required by researchers and scientists working on radiation shielding properties of multi-component materials.
AtıfWoS85OpenAlex93İncele - MakaleYalnız künye2021Scopus SJRQ4Influence of the Infusion Time on the Phenol Content and the antioxidative Activity of Herbal and Fruit Teas
Kara, H. H.; Erdogan, T.; Demirbas, F.; Bor, Y.; Cakiroglu, K. Aksehir
- MakaleYalnız künye2021Scopus SJRQ4Effects of Bifidobacterium animalis and inulin addition on quality characteristics of synbiotic milk chocolate
Akgül, Ayse; Sert, Durmus; Mercan, Emin
The aim of this study was to investigate effects of addition of B. animalis BB-12 (before tempering, BT or after tempering, AT) and inulin (6, 8, and 10%) on thermal, physicochemical characteristics, fatty acid composition, textural properties and probiotic viability of milk chocolates during 60 days of storage. The free fatty acid (FFA) value of milk chocolates ranged from 0.66 to 0.89 (% oleic acid), in which higher ratio of inulin addition increased the FFA. Probiotics and inulin addition increased darkness of chocolates when compared to control. D[4,3] value of samples ranged from 9.26-17.97 mu m. Higher inulin ratio in chocolates increased viscosity and yield value. These values in the group BT were higher than those of the group AT. BB-12 count of probiotic and synbiotic samples ranged from 7.09-8.06 log cfu/g during the storage. Higher inulin ratio increased the probiotics count in samples. Probiotic addition after tempering increased the count of probiotic and improved viability at the end of storage. The results showed that B. animalis BB-12 is capable of surviving in milk chocolate, at an appropriate bacteria count (>107 cfu/g), up to 60 days of storage at 18 degrees C.
AtıfWoS2İncele - MakaleYalnız künye2021Effect of testicular morphology on embryo development to the blastocyst stage after round spermatid injection
Ozmerdiven, Gokhun; Guler, Yavuz; Sahin, Eren; Tatar, Zeynep; Erbin, Akif; Dirican, Ebubekir; Haliloglu, Ahmet Hakan
If spermatozoa cannot be found after testiculer sperm extraction (TESE) in patients followed up due to nonobstructive azospermia (NOA) and the patients do not want donor spermatozoa, performance of round spermatid injection (ROSI) with the current technology seems to be the last resort. This retrospective study was conducted to evaluate the effect of testicular morphology on the development of embryos to the blastocyst stage obtained from ROSI. Between September 2019 and March 2020, after TESE and biopsy 29 patients who had only spermatid were taken to study. Tubular appearance, basal membrane appearance, Johnson score, peritubular fibrosis, interstitial fibrosis, and Leydig cell proliferation were pathologically examined. Following egg collection, ROSI was applied to the oocytes using the piezoelectric method. The embryos were monitored until the blastocyst stage. The mean age of the 29 patients was 36.3+5.01 years. Also, 7 patients had not previously undergone TESE, 20 had previously undergone once, and 2 had previously undergone twice. It was observed that having a history of TESE and a high Johnson score increased the likelihood of the embryo remaining in the blastocyst stage (P=0.021 and 0.014, respectively). However, other parameters do not affect the likelihood of blastocyst formation (P>0.05). Low TESE history and high Johnson score were associated with embryo development to the blastocyst stage. If spermatozoa are not found in patients with nonobstructive azoospermia, ROSI performed during initial TESE increases the likelihood of blastocyst formation.
AtıfWoS1İncele - MakaleYalnız künye2021BIOCHEMICAL AND BIOACTIVE CONTENT IN FRUITS OF WALNUT (JUGLANS REGIA L.) GENOTYPES FROM TURKEY
Erdogan, Ummugulsum; Argin, Sanem; Turan, Metin; Cakmakci, Ramazan; Olgun, Murat
Walnuts (Juglans regia L.) are a good source of dietary minerals and contain significant amounts of potassium, phosphorus, magnesium and iron. In Turkey, walnut orchards are found in the coruh Valley and are generally composed of local varieties. Since chemical and physical properties of walnuts are very important in determining their quality, in this study, nut and kernel characteristics, fatty acid composition and phenolic composition were determined for 26 walnut genotypes collected from the valley. Total fat content was found to be between 53.75% and 71.43%, while the crude protein amount ranged from 10.21% to 20.71%. Total carbohydrates were calculated between 14.31-27.52% and ash content was found to be between 1.64% and 3.32%. The oleic acid content and linoleic acid content ranged from 18.34 to 25.58% and 37.09% to 87.51%, respectively. The linolenic acid content was determined between 5.52% and 11.03%. Our study showed that, differences in phenolic component, crude protein and fatty acid content of walnuts were caused by different growing conditions. Genotypes have a rich and stable structure in terms of fruit quality parameters, minerals, organic acids, phenolic composition, antioxidant and fatty acids amounts and amino acids. In other words, these characteristics did not show much variation in genotypes grown in the Valley. However, there was a great variation in hormone levels among genotypes. In terms of the parameters examined, GN2, GNI, ((NIS, GN24, GN25 and GN26 genotypes were determined as rich and stable genotypes.
AtıfWoS8İncele - MakaleYalnız künye2021Scopus SJRQ1Enhancing Burnability Characteristics of Low-Temperature Burnt-Cement Clinker by Recycling Phosphogypsum Wastes
Aksan, U.; Köseoglu, K.; Gökçe, H. S.
In the present study, the effect of phosphogypsum, a byproduct from the phosphoric acid production industry, on the clinkerization process was researched in order to improve the burnability of clinkers at lower burning temperatures. Raw meal samples containing phosphogypsum at 0%, 1%, 3%, and 5% by weight were burned at 1,350 degrees C, 1,400 degrees C, 1,450 degrees C, and 1,500 degrees C. The introduction of phosphogypsum reduced the presence of unbounded (free) CaO relatively up to 43%. Thus, the mineralization effect of phosphogypsum promotes lower burning temperatures. The free CaO content of the 5% phosphogypsum containing clinker decreased to 0.94% at 1,400 degrees C after 120 min of burning time. The free CaO content was found to be almost identical (0.75%) to that of industrial clinker burned in a rotary kiln at 1,500 degrees C. Due to the low free CaO content (<1%) and the burnability index (73), the recycling of phosphogypsum wastes was found to be suitable for the production of eco-efficient clinkers. The reduced energy consumption and energy-related CO2 emissions in such modified clinkers can contribute to the economic and ecological goals of the cement industry. (C) 2021 American Society of Civil Engineers.
AtıfWoS2OpenAlex3İncele - MakaleYalnız künye2021Scopus SJRQ3Biocatalytic asymmetric synthesis of (R)-1-tetralol using Lactobacillus paracasei BD101
Kalay, Erbay; Şahin, Engin
Asymmetric bioreduction of ketones is a fundamental process in the production of organic molecules. Compounds containing tetralone rings are found in the structure of many biologically active and pharmaceutical molecules. Biocatalytic reduction of ketones is one of the most promising and significant routes to prepare optically active alcohols. In this study, the reductive capacity of Lactobacillus paracasei BD101 was investigated as whole-cell biocatalyst in the enantioselective reduction of 1-tetralone (1). In biocatalytic reduction reactions, the conversion of the substrate and the enantiomeric excess (ee) of the product are significantly affected by optimization parameters such as temperature, agitation rate, pH, and incubation time. Effects of these parameters on ee and conversion were investigated comprehensively. (R)-1-tetralol ((R)-2), which can be used to treat disorder such as obsessive compulsive, post-traumatic stress, premenstrual dysphoric, and social anxiety, was manufactured in enantiopure form, high yield and gram-scale, using whole-cell biocatalysts of L. paracasei BD101. The 7.04 g of (R)-2 was obtained in optically pure form with 95% yield. Also, to our knowledge, this is the first report on production of (R)-2 using whole-cell biocatalyst in excellent yield, conversion, enantiopure form and gram scale. This is a clean, eco-friendly and cheap method for the synthesis of (R)-2 compared with chemical catalyst.
AtıfScopus23WoS23OpenAlex24
İncele - Kitap BölümüYalnız künye2021Is a New Understanding of Tourism after Covid-19 Possible?
Çelebı Boz, Füsun; Gültekın, Ömer Faruk
- MakaleYalnız künye2021Scopus SJRQ1The Online Learning Experience of Theology Students in Turkey during the COVID-19 Pandemic: A New Disposition for RE?
Selçuk, Mualla; Sözen, Hasan; Şimşek, Vahdeddin; İpek, Yasemin
Through a quantitative research model, this study aims to understand the general attitudes of theology students in Turkey regarding online learning during the COVID-19 pandemic. In examining the determinant factors on their attitudes, research findings include: previous online education experience, the frequency of participating in synchronous courses, the qualifications of the instructor, the assessment and evaluation procedures, the orientation training programs and the infrastructure opportunities of the universities. Interpreting these factors enables the authors of this article to suggest a conversational relationship between RE and Islamic sciences with some shared objectives that leads to naming guiding principles in a manner that significantly supports students’ vocational journey.
AtıfScopus5WoS5OpenAlex19İncele - MakaleYalnız künye2021Scopus SJRQ1Development of gelatine-based edible film by addition of whey powders with different demineralisation ratios: Physicochemical, thermal, mechanical and microstructural characteristics
Sert, Durmuş; Üçok, Gamze; Kara, Ümmügülsüm; Mercan, E.M.İ.N.
The effects of using whey powders with different demineralisation rates on the physicochemical, thermal, mechanical, and microstructural properties of gelatine-based edible films were investigated. Films were produced from film-forming solutions (FFS) containing whey powder (WP) and 50, 70 and 90% demineralised whey powder (50DWP, 70DWP, 90DWP). The addition of whey powders increased the pH and particle size values of FFS. The zeta potential decreased significantly in the WP sample and gradually reduced depending on the demineralisation rate in the DWP samples. The addition of whey powders partially increased the density of the films. WP addition reduced the hydrophobicity of the film, while the addition of DWPs did not cause any change. The addition of whey powders decreased the L* and a* values of the films while increasing the b* values. Control was the most transparent, while 70DWP and 90DWP films had higher opacity. WP films had the most uniform and smooth surface. The highest degradation temperature (269.64 °C) was observed in the control sample. The weight loss of the control was 95%, whereas those of WP and DWP samples were 88–89%. WP addition reduced the tensile strength and increased the elasticity of the films.
AtıfScopus12WoS10OpenAlex12İncele - Kitap BölümüYalnız künye2021An Unsupervised Learning Framework to Analyze the Economic Impact of Covid-19: An Application on the Most Affected Countries
Özden, Erdemalp
- MakaleYalnız künye2021Scopus SJRQ3Two-dimensional frictionless contact analysis of an orthotropic layer under gravity
Öner, Erdal
An analytical method for solving the two-dimensional frictionless continuous contact problem of an orthotropic layer pressed by a rigid stamp is presented in this paper. The orthotropic layer lies on a rigid foundation, and plane-strain orthotropy prevails in the layer, which is not bonded to the rigid foundation. An external load was applied to the orthotropic layer through a rigid stamp. The profiles of flat and cylindrical stamps as stamp shapes were handled separately. The orthotropic layer was assumed to be subjected to uniform vertical body forces owing to the effect of gravity. For values of the resultant compressive force P acting on the stamp vertically that were lesser than a critical value, the continuous contact along the orthotropic layer–rigid foundation interface was maintained. By assuming plane-strain conditions, the governing equations corresponding to the mentioned contact problem were extracted separately in the presence and absence of the body force of the orthotropic layer using the theory of elasticity and the Fourier integral transformation technique. Subsequently, the mixed boundary value problem was reduced to a singular integral equation, and the numerical solution of this singular integral equation was obtained by applying the Gauss–Chebyshev integration formulas. Numerical results reveal the effect of the orthotropic material parameters, stamp length (in the case of a flat stamp), stamp radius (in the case of a cylindrical stamp), applied load on the contact stress distributions, contact length, initial separation load and initial separation distance. The results of this study may provide insights for engineers in fields closely related to contact mechanics.
AtıfScopus29WoS29OpenAlex26İncele - MakaleYalnız künye2021Scopus SJRQ1An investigation of the fatigue performance of adhesively bonded step-lap joints: An experimental and numerical analysis
Gavgali, Esma; Sahin, Resul; Akpinar, Salih
Adhesively bonded joints are used in many engineering applications and are manufactured by joining various materials together. Static and dynamic analysis of adhesively bonded joints is very important in both scientific and sector studies on these joints. In this study, the static and fatigue strengths of single-lap joints (SLJs) and three-step-lap joints (TSLJs) that were subjected to tensile and four-point bending tests were examined experimentally and numerically. Adhesively bonded joints were produced using DP460 toughened type adhesive and AA2024-T3 aluminum alloy was used as the adherent. Fatigue tests were performed at a loading ratio (R) of 0.1 and a frequency of 10 Hz. As a result, applying a step-lap to the overlap area of adhesively bonded joints considerably increased the tensile static and fatigue strength of the joint. For the single-lap joint, both the static tensile and the tensile fatigue lifetime limit value of the three-step-lap joint increased approximately 100%. One of the reasons for that increase was that the moment effect formed in single lap joints due to the eccentric loading is minimized and the other is that a step-lap applied to the overlap area retards the formation of damage. However, static bending and fatigue strength values of TSLJs significantly decreased compared to those of SLJs. In addition, the results of the experimental and numerical analyses were found to be highly compatible with each other.
AtıfScopus29WoS28OpenAlex35İncele - MakaleYalnız künye2021Scopus SJRQ1An embedded mixed method study on teaching algebraic expressions using metacognition-based training
Öztürk, Mesut
That the students are aware of the learning process and know how they learn is important in terms of both controlling their previous learning and building their new learning on the previous ones. This thinking process, which generally requires metacognitive skills, may facilitate the difficulties experienced by the students while passing on from arithmetic to algebraic thinking. This study had two purposes:(1) to examine the effect of the IMPROVE method, a metacognitive training method, on the academic achievement of middle school students regarding algebraic expressions and (2) to examine the teaching process of algebraic expressions with IMPROVE. This study was conducted as an embedded mixed design. Forty-nine sixth grade students participated in the quantitative part of the study, while only six students from the experimental group participated in the qualitative part. The quantitative results of the study showed that there was a significant difference between the students’ total achievement scores regarding algebraic expressions and the achievement scores in the questions requiring high-level thinking skills in favor of the experimental group. It has been found in the comparisons made based on cognitive field levels that there is a statistically significant difference in favor of the group that received metacognition-based education in synthesis level questions. The qualitative results indicated that this teaching method increased students’ interest, contributed to their conceptual learning and improved their various affective characteristics. Also, it has been determined that the students who receive metacognition-based education do enjoy learning with this teaching method and that they think this method should be sustainable for the upcoming lessons.
AtıfScopus15WoS10OpenAlex22İncele - MakaleYalnız künye2021Scopus SJRQ3Synthesis of silver nanoparticles prepared with a dextran-type exopolysaccharide from Weissella cibaria MED17 with antimicrobial functions
İspirli, Hümeyra; Sagdic, Osman; Dertli, Enes
Microbial polysaccharides can find distinct applications as stabilizer agents including synthesis of nanoparticles. In this study, a dextran-type exopolysaccharide (EPS) was used as the stabilizer agent for the green synthesis of silver nanoparticles (AgNPs-Dex) with antimicrobial characteristics. UV–vis spectroscopy analysis was used to test the formation of AgNPs-Dex. The uniform morphology at around 10 nm size was observed for AgNPs-Dex by TEM analysis and importantly EDX analysis demonstrated the embedment of Ag+ ions within dextran as the stabilizer agent. XRD analysis confirmed the crystalline nature of AgNPs-Dex and FTIR analysis demonstrated the interactions of dextran functional groups with silver. DSC and TGA analysis showed the alteration in the thermal stability of AgNPs-Dex compared to the stabilizer dextran. The antibacterial and antifungal activities of AgNPs-Dex were determined against food originated pathogenic bacteria and fungi and important inhibition levels were observed at 1 mg ml−1 concentration of AgNPs-Dex and this activity was observed to be concentration dependent.
AtıfScopus17WoS13OpenAlex15İncele - MakaleYayıncıda açık erişim2021Scopus SJRQ3The effect of different microbial fertilizer doses on yield and yield components in coriander (Coriandrum sativum L.)
Gül, Volkan; Öztürk, Erdoğan
Microbial fertilizers containing Bacillus subtilis and Bacillus megaterium isolates are one of the important organic fertilizers, which strengthen the immune system of plants against harmful effects and promote the plant growth by fixing nitrogen from the atmosphere, to obtain better quality products. This study was conducted to determine the effects of different liquid microbial fertilizer doses (0, 500, 1000, 1500, 2000, and 2500 ml 100 L–1) on the yield and yield components of the coriander (Coriandrum sativum L.) grown in Bayburt in 2018 and 2019. The experiment was set up as three replicates in randomized complete block design. The results indicated that there was a considerable variation in the yield and yield components of coriander, and the yield significantly increased as the dose of microbial fertilizer was increased. The maximum essential oil content and seed yield were recorded for the plots grown under the F1 and F3 treatment. It was found that the maximum seed yield was obtained in the F3 treatment (839.0 kg ha–1), and the seed yield decreased in the F4 (754.1 kg ha–1) and F5 (759.9 kg ha–1) treatments. Although the increase in the microbial fertilizer dose increases seed yield, using the fertilizer in optimum dose can be more profitable. Therefore, this study suggests that the fertilizer dose “F3” can improve the productivity of the coriander grown in the areas treated with microbial fertilizer.
AtıfScopus5WoS5OpenAlex4İncele - MakaleYalnız künye2021Scopus SJRQ1Orange, red and purple barberries: Effect of in-vitro digestion on antioxidants and ACE inhibitors
Şensu, Eda; Kasapoğlu, Kadriye Nur; Gültekin-Özgüven, Mine; Demircan, Evren; Arslaner, Ayla; Özçelik, Beraat
Bioactive compounds such as phenolics, anthocyanins and carotenoids were investigated in Berberis plant with purple (PB), red (RB) and orange (OB) fruits (barberries). The study was aimed to evaluate the bioaccessibility of the antioxidants and ACE (angiotensin converting enzyme) inhibitory compounds of barberry plants upon their transit through in-vitro digestion. Among barberries, (PB) exhibited the strongest antioxidant activity due to its higher phenolic and flavonoid content. The order of total phenolics and anthocyanins was PB > RB > OB. Chlorogenic acid was the main phenolic compound in all barberries even after in-vitro digestion. All barberries had similar amounts of total carotenoids (4.45 mgβ-carotene/100gDW). After in-vitro digestion, decreasing phenolics, anthocyanins and carotenoids led to a reduced antioxidant activity. Anthocyanins were found the most sensitive compounds in-vitro digestion. In terms of ACE inhibition activity, only RB exhibited ACE inhibition before (73.84%) and after (65.51%) in-vitro digestion. No ACE inhibition activity was detected at all in RB and OB samples. Leaves and branches of Berberis had also over 50% ACE inhibitory activity. To our knowledge, this is the first study on the carotenoids of barberry and the effect of in-vitro digestion on its bioactive compounds and ACE inhibitors.
AtıfScopus30WoS22OpenAlex26İncele - MakaleYalnız künye2021Scopus SJRQ1The effects of nanostructure additive on fracture strength in adhesively bonded joints subjected to fully reversed four-point bending fatigue load
Demir, Kübra; Gavgali, Esma; Yetim, Ali Fatih; Akpinar, Salih
Structural adhesive joints used in aerospace are usually subjected to fatigue loading rather than static loading. This study experimentally and numerically investigated the static four-point bending loads of adhesively bonded joints after fully reversed four-point bend fatigue loading where nanoadhesives – obtained by adding carbon nanostructures into aerospace grade structural adhesive – were used to bond the joints. Single lap joint specimens were produced using a nanocomposite adhesive obtained by adding 1 wt % graphene, 1 wt % carbon nanotubes-COOH and 1 wt % fullerene C60 nanostructures to a DP460 structural adhesive. AA2024-T3 aluminum alloy and carbon fiber-reinforced composites (CFRCs) with a plain weave fabric (0/90°) were used as adherend materials. First, static four-point bending tests were applied to these joints to obtain their strengths and then fully reversed sinusoidal fatigue tests were applied under a constant load amplitude, a frequency of 20 Hz and a load ratio of R = −1. Fatigue tests were performed over 1,000,000 cycles – accepted as an infinite life – at four different load levels by considering the strengths obtained from the static tensile tests. After obtaining the static four-point bending strengths of the joints to which fatigue loading was applied, the changes in the strengths of joints with and without fatigue testing were examined. The static strengths of aluminum joints bonded with nanoadhesive and subjected to fully reversed fatigue loading significant increased, depending on the nanostructure type added to the adhesive. Moreover, such increases in the strengths of joints are highly dependent on the adherend type (composite with [0/90]6 stacking sequence or AA2024-T3 aluminum).
AtıfScopus34WoS34OpenAlex34İncele - MakaleYalnız künye2021Scopus SJRQ3Regioselective asymmetric bioreduction of trans-4-phenylbut-3-en-2-one by whole-cell of Weissella cibaria N9 biocatalyst
Kalay, Erbay; Şahin, Engin
There is a considerable interest in the asymmetric production of chiral allylic alcohols, the main building blocks of many functional molecules. The asymmetric reduction of α,β-unsaturated ketones is difficult with traditional chemical protocols in a regioselective and stereoselective manner. In this study, the reductive capacity of whole cell of Leuconostoc mesenteroides N6, Weissella paramesenteroides N7, Weissella cibaria N9, and Leuconostoc pseudomesenteroides N13 was investigated as whole-cell biocatalysts in the enantioselective reduction of (E)-4-phenylbut-3-en-2-one (1). The biocatalytic reduction of 1 to (S,E)-4-phenylbut-3-en-2-ol ((S,E)-2) using the whole cell of W. cibaria N9 isolated from Turkish sourdough was developed in a regioselective fashion, occurring with excellent conversion and recovering the product in good yield. In biocatalytic reduction reactions, the conversion of the substrate and the enantiomeric excess (ee) of the product are significantly affected by optimization parameters such as temperature, agitation rate, pH, and incubation time. Effects of these parameters on ee and conversion were investigated comprehensively. In addition, to our knowledge, this is the first report on production of (S,E)-2 using whole-cell biocatalyst in excellent yield, conversion with enantiopure form and at gram scale. These findings pave the way for the use of whole cell of W. cibaria N9 for challenging higher substrate concentrations of different α,β-unsaturated ketones for regioselective reduction at industrial scale.
AtıfScopus21WoS21OpenAlex23İncele