Mustafa Esen Marti - Academia.edu (original) (raw)

Papers by Mustafa Esen Marti

Journal of Bioscience and Bioengineering, Mar 1, 2016

While Schwann cells (SCs) have a significant role in peripheral nerve regeneration, their use in ... more While Schwann cells (SCs) have a significant role in peripheral nerve regeneration, their use in treatments has been limited because of lack of a readily available source. To address this issue, this study focused on the effect of guidance cues by employing micropatterned polymeric films to influence the alignment, morphology and transdifferentiation of bone marrow-derived rat mesenchymal stem cells (MSCs) towards a Schwann cell (SC)-like fate. Two different types of polymers, biocompatible polystyrene (PS) and biodegradable poly(lactic acid) (PLA) were used to fabricate patterned films. Percentages of transdifferentiated MSCs (tMSCs) immunolabeled with SC markers (α-S100β and α-p75 NTR) were found to be similar on patterned versus smooth PS and PLA substrates. However, patterning had a significant effect on the alignment and elongation of the tMSCs. More than 80% of the tMSCs were oriented in the direction of microgrooves (0 o-20 o), while cells on the smooth substrates were randomly oriented. The aspect ratio [AR, ratio of length (in direction of microgrooves) and breadth (in direction perpendicular to microgrooves)] of the tMSCs on patterned substrates had a value of approximately five, as compared to cells on smooth substrates where the AR was one. Understanding responses to these cues in vitro helps us in understanding the behavior and interaction of the cells with the 3D environment of the scaffolds, facilitating the application of these concepts to designing effective nerve guidance conduits for peripheral nerve regeneration.

Environmental progress & sustainable energy, Sep 8, 2016

If biosurfactants are to achieve their promise in environmental oil-spill remediation, their toxi... more If biosurfactants are to achieve their promise in environmental oil-spill remediation, their toxicity to marine life must be assessed. A killifish larvae assay is commonly used as a measure of toxicity but is difficult and nonlinear in response. Red blood cell (RBC) hemolysis has also been the basis for assays of some surfactant levels. Here we present a modified sheep RBC suspension assay and compare its response to that of the fish assay for surfactin and its genetically modified variant fatty-acyl-glutamate (FA-Glu). This is the first report of hemolytic activity as a property of FA-Glu. The method's potential for screening for toxicity against marine organisms is demonstrated. V

Selcuk University Journal of Engineering, Science and Technology, Mar 1, 2017

Today many carboxylic acids are recovered from biological production media and industrial wastewa... more Today many carboxylic acids are recovered from biological production media and industrial wastewaters. Reactive extraction is favored over other separation methods due to its high recovery efficiency, ease of operation, low energy demand and reduced cost. However, use of toxic organic diluents in the organic phases is the main disadvantage of the method. In this study, the appropriateness of an environmentally-friendly solvent, sunflower oil (SFO) to be used as organic phase diluent during the recovery of formic acid (FA) from aqueous solutions by reactive extraction was evaluated. Alamine-336 was used as the extractant and the results obtained with SFO were compared with those obtained using octanol. The separation process reached an equilibrium in 3 hours and the recovery efficiency increased with the increase in extractant percentages. The initial FA concentration positively influenced the recovery when SFO was used as the diluent. In the ranges of the parameters studied, the highest recovery values were 98.6% and 82.6% with octanol and SFO, respectively. This study shows that low molecular weight carboxylic acids, e.g. FA can be recovered from aqueous solutions by reactive extraction using environmentally-friendly solvents such as SFO.

Enzyme and microbial technology, Feb 1, 2014

Two biosurfactants, surfactin and fatty acyl-glutamate, were produced from genetically-modified s... more Two biosurfactants, surfactin and fatty acyl-glutamate, were produced from genetically-modified strains of Bacillus subtilis on 2% glucose and mineral salts media in shake-flasks and bioreactors. Biosurfactant synthesis ceased when the main carbohydrate source was completely depleted. Surfactin titers were ∼30-fold higher than fatty acyl-glutamate in the same medium. When bacteria were grown in large aerated bioreactors, biosurfactants mostly partitioned to the foam fraction, which was recovered. Dispersion effectiveness of surfactin and fatty acyl-glutamate was evaluated by measuring the critical micelle concentration (CMC) and dispersant-to-oil ratio (DOR). The CMC values for surfactin and fatty acyl-glutamate in double deionized distilled water were 0.015 and 0.10 g/L, respectively. However, CMC values were higher, 0.02 and 0.4 g/L for surfactin and fatty acyl-glutamate, respectively, in 12 parts per thousand Instant Ocean®[corrected].sea salt, which has been partly attributed to saline-induced conformational changes in the solvated ionic species of the biosurfactants. The DORs for surfactin and fatty acyl-glutamate were 1:96 and 1:12, respectively, in water. In Instant Ocean® solutions containing 12 ppt sea salt, these decreased to 1:30 and 1:4, respectively, suggesting reduction in oil dispersing efficiency of both surfactants in saline. Surfactant toxicities were assessed using the Gulf killifish, Fundulus grandis, which is common in estuarine habitats of the Gulf of Mexico. Surfactin was 10-fold more toxic than fatty acyl-glutamate. A commercial surfactant, sodium laurel sulfate, had intermediate toxicity. Raising the salinity from 5 to 25 ppt increased the toxicity of all three surfactants; however, the increase was the lowest for fatty acyl-glutamate.

Industrial & Engineering Chemistry Research, Nov 2, 2011

Interest in pyruvic acid has been growing due to the increase in its potential areas of use and i... more Interest in pyruvic acid has been growing due to the increase in its potential areas of use and its importance in metabolic reactions. These reasons along with the limitations on recovery have prompted researchers to consider novel recovery techniques. Reactive extraction has been proposed as a promising approach to the recovery of carboxylic acids. In this study, equilibrium and kinetic data were obtained for reactive extraction of pyruvic acid using trioctylamine (TOA) or Alamine 336 in 1-octanol or oleyl alcohol. The results showed that, without pH adjustment in the aqueous phase, and without the use of an extractant, 1-octanol extracted more pyruvic acid than oleyl alcohol with a distribution coefficient (K D) of 0.30. This trend remained the same when tertiary amines were used as an extractant. The K D values did not significantly differ with TOA or Alamine 336. The recovery of pyruvic acid was observed to increase as a function of TOA concentration and the stoichiometry of the reaction was mainly 1:1. As tertiary amines react only with undissociated acids, an increase in the initial pH of the aqueous phase lowered the K D values. When the pH was 4.0, the effect of TOA concentration on pyruvic acid extraction disappeared and for all concentration levels a distribution coefficient of 0.10 was obtained. Kinetic measurements showed that the reaction between pyruvic acid and TOA in 1-octanol is first order with respect to the two reactants with a rate constant of 0.94 L mol À1 s À1. The enhancement factor was calculated as 25.

Journal of Water Process Engineering

Separation Science and Technology, Jun 22, 2016

ABSTRACT Combined use of inert diluents with polar modifiers enables former to be utilized for th... more ABSTRACT Combined use of inert diluents with polar modifiers enables former to be utilized for the recovery of polar value-added chemicals. The results show that polarities of both solvent and modifier are critical for efficient separations. Thus, KD values with 1-octanol were higher than those with 1-decanol; however, those with xylene were superior to those with hexane and toluene. Increasing the amine concentrations increased the KD values, in contrast to the trends with pH and temperature. About 33%, 79% and 67% of acetic acid was recovered using 25% (v/v) Alamine 336 in xylene, 1-octanol and 30% 1-octanol-modified xylene, respectively. Therefore, solvent modification positively affects the extraction power of inert diluents for acetic acid recovery.

Turkish Journal of Chemistry

Introduction One of the most widely manufactured polymers in industry is polypropylene (PP). Its ... more Introduction One of the most widely manufactured polymers in industry is polypropylene (PP). Its global market size was around USD 117.8 billion in 2020 and is projected to increase at an annual growth rate of 3.4% from 2021 to 2028 [1]. PP is synthesized via polymerization reaction of propene molecules and high purity of the monomers used in the process is strictly required for an efficient process. Practically 2/3 of the propene in industry is used for the production of PP [2]. Besides, it is employed for the manufacture of propene oxide (epoxypropane), acrylic (propenoic) acid, acrylonitrile (propenenitrile), butanol, and (1-Methylethyl) benzene (cumene) [1-3]. Propene is currently produced as a by-product fluid catalytic cracking and coproduct of naphtha catalytic cracking [3]. Propene obtained from refineries can be used in liquefied petroleum gas or to enhance the octane number in gasoline [1,2]. However, even negligible amounts of impurities can prevent the polymerization of propene into polypropylene. In addition, current production methods use huge amounts of energy, which also negatively influenced the greenhouse emissions [4,5]. Propene can be alternatively produced by catalytic dehydration of propan-2-ol (Eq. 1) [6]. In addition, this reaction is a probe to determine the acid-base sites of the solid catalysts [7]. In this context, the presence of acid sites (Brønsted and/ or Lewis) on the catalyst lead propene formation by dehydration, whereas acetone is formed via the dehydrogenation of propanol-2-ol (Eq.2) in the presence of basic sites or acid-base couples [3,8-17]. CH 3-CHOH-CH 3 → CH 3-CH=CH 2 + H 2 O (1) CH 3-CHOH-CH 3 → CH 3-CO-CH 3 + H 2 (2) In the literature, mainly supported catalysts have been employed for the dehydrogenation of propan-2-ol while various metal oxide catalysts were studied for the catalytic dehydration of propan-2-ol [9-22]. For example, Cu/Al 2 O 3 catalysts were used for the selective dehydrogenation of propan-2-ol to form acetone [10]. Moreover, high selectivity was obtained with Pt/ZrO 2 catalyst at the temperatures lower than 250 °C (T < 250 °C) for acetone formation [11]. Au/CeO 2 catalysts were reported to enhance the selectivity towards acetone by suppressing the dehydration of propan-2-ol [12]. Lately, CuO x PtO x /TiO 2-ZrO 2 catalysts showed high efficiency and selectivity due to their basic properties [13]. Supports are

Research on Chemical Intermediates

DESALINATION AND WATER TREATMENT

Today, water pollution is one of the major problems threatening human health. Synthetic dyes from... more Today, water pollution is one of the major problems threatening human health. Synthetic dyes from industrial effluents are among the many toxic compounds that cause water pollution. The aim of this study is the evaluation of olive pomace (OP) to be used as a biosorbent during the separation of two anionic dyes, Congo Red (CR) and Methyl Orange (MO), from aqueous solutions by adsorption technique. The biosorbent was characterized using Fourier transform infrared, Brunauer-Emmett-Teller, Barrett-Joyner-Halenda, and scanning electron microscopy with energy-dispersive X-ray spectroscopy. It was shown to be largely unaffected by pH, indicating that OP can be utilized over a wide pH range. Experiments were conducted without pH adjustment of aqueous solutions. Kinetics showed that adsorption followed the pseudo-second-order kinetic model and reached equilibrium in 210 min. Efficiency reduced with the increase in temperature and thermodynamic parameters indicated that physical or physico-chemical interactions may have occurred between the dyes and OP. The process was exothermic and non-spontaneous. The efficiency was negatively influenced by initial dye concentration while positively affected by the OP dose. The trend was reversed for adsorption capacity, resulting in maximum values of 145.0 and 257.4 mg/g for CR and MO, respectively. These were higher than those reported in the literature for the sorption of these dyes using various types of waste materials. The process was well-explained by Freundlich isotherm for both dyes. The OP was found to be effective for the separation of anionic dyes from aqueous solutions over wide pH and concentration ranges.

International Journal of Environmental Science and Technology

Gunumuzde pek cok karboksilik asit biyolojik uretim ortamlarindan ve endustriyel atik sulardan ge... more Gunumuzde pek cok karboksilik asit biyolojik uretim ortamlarindan ve endustriyel atik sulardan geri kazanilmaktadir. Tepkimeli ozutleme, yuksek geri kazanim verimi, islem basitligi, dusuk enerji gereksinimi ve maliyeti nedeniyle diger ayirma yontemlerine tercih edilmistir. Fakat organik fazlarda zehirli organik seyrelticilerin kullanimi yontemin en onemli dezavantajidir. Bu calismada cevre dostu bir cozucunun, aycicek yaginin formik asidin sulu cozeltilerinden tepkimeli ozutleme yontemi ile geri kazanimi sirasinda organik faz seyrelticisi olarak zehirli organik kimyasallar yerine kullanimi degerlendirilmistir. Ozutleyici olarak Alamine-336 kullanilmis ve aycicek yagi ile elde edilen sonuclar oktanol ile elde edilen sonuclarla karsilastirilmistir. Ayirma sureci 3 saatte dengeye ulasmis ve geri kazanim verimi ozutleyici yuzdesi ile birlikte artmistir. Aycicek yagi seyreltici olarak kullanildiginda baslangic asit derisimi geri kazanimi pozitif yonde etkilemistir. Calisilan degisken ara...

Journal of Chemical & Engineering Data, 2019

Wastewaters containing organic compounds such as acids, ketones, phenols, and amines can cause cr... more Wastewaters containing organic compounds such as acids, ketones, phenols, and amines can cause critical environmental problems depending on their concentration and composition. Efficient and low-cost separation of these components may also bring their reuse in industry while cleaning the aqueous streams. Formic acid (FA) is an important raw material in industry and is widely seen in wastewaters. In this study, two different anion exchangers were compared for the separation of FA from aqueous solutions. Effects of process parameters and the mechanism were discussed. Kinetic, equilibrium, and thermodynamic studies were performed, and the data were interpreted using the relevant isotherm and kinetic models. The results showed that Lewatit MP-64 was more efficient than Amberlite IRA-96 in the range of the parameters studied. The maximum adsorption capacity obtained with Lewatit MP-64 (442.75 mg/g) was significantly higher than that were previously reported in the literature for FA separation. The data were well explained by the Langmuir isotherm model. However, relatively high R 2 values were obtained with Temkin and Freundlich isotherms. Therefore, further studies are ongoing to clarify the mechanism.

Selcuk University Journal of Engineering ,Science and Technology, 2017

Separation and Purification Technology, 2015

In this study, a multi-stage reactive extraction system is devised for the selective recovery of ... more In this study, a multi-stage reactive extraction system is devised for the selective recovery of pyruvic acid (PA) from a multiple-acid solution having a carboxylic acid composition identical to that obtained in microbial fermentation. With single-stage extraction, approximately 40% of the acetic acid (AA) is preferentially and selectively recovered from the aqueous three-acid solution using 0.1 M trioctylamine (TOA) in 1-octanol. Pyruvic acid is the only solute positively affected by an increase in the TOA concentration; however, the purity of the final extract is compromised by co-extracted acids. The distribution coefficient (K D) values obtained in three-acid solutions are lower than those obtained in single-acid solutions, showing the antagonistic effects due to the presence of other acids. However, in two-acid solutions, the presence of lactic acid (LA) at an initial concentration of about 7-20% (0.05-0.15 M) of that of PA (0.75-0.85 M) causes an increase of 33-80% on the K D of the latter. Using 0.6 M TOA in 1-octanol, 92% of initial PA is recovered from the two-acid solution. The competition with the other acid(s) for ion pair formation and its marked hydrophilicity hinders the extraction of LA from multiple acid solutions. Thus, a successful selective separation is achieved for the three acids present in the aqueous phase. A further increase in the initial concentration ratio of LA to PA in two-acid solution results in reduced K D values for the latter. The maximum separation factor of 54.3 is obtained at the lowest acid ratio (AR, 0.19) and highest TOA concentration (0.6 M). Hence, reactive extraction can be successfully employed to selectively recover PA from two and three-acid aqueous solutions.

Separation Science and Technology, 2016

Selcuk University Journal of Engineering Science and Technology, Nov 27, 2013

S U Muhendislik Bilim Ve Teknoloji Dergisi, Nov 27, 2013

Karboksilik asitlerin üretim ortamlarından veya atık sulardan geri kazanımı için düşük maliyetli ... more Karboksilik asitlerin üretim ortamlarından veya atık sulardan geri kazanımı için düşük maliyetli ayrıştırma yöntemlerine ihtiyaç duyulmaktadır. Formik asit, en basit karboksilik asit olup sıklıkla antibakteriyel ve koruyucu madde olarak endüstride yer bulmaktadır. Bu çalışmada endüstride geniş kullanım alanı olan formik asidin sulu çözeltilerinden tepkimeli özütleme ile yüksek verimde geri kazanılması amaçlanmıştır. 1-oktanol, hekzan ve ksilen seyreltici olarak seçilirken; bir uzun zincirli üçüncül amin karışımı olan Alamine 336, özütleyen olarak kullanılmıştır. Geri kazanım yüzdesini artırmak amacıyla inert seyrelticiler (ksilen ve hekzan), nispeten daha polar bir çözücüyle modifiye edilmişlerdir. Çözücü türü, modifiye edici oranı ve özütleyen derişiminin formik asidin tepkimeli özütlenmesine etkileri incelenmiştir. Denge verileri kullanılarak dağılım katsayısı (D) ve yükleme oranı değerleri (z) hesaplanmıştır. Çalışılan seyrelticilerden en yüksek D değerleri 1-oktanol ile elde edilmişlerdir. Inert seyrelticilerin modifiye edilmesi daha yüksek özütleme verimi ile sonuçlanmıştır. Eğilim, Alamine 336 içeren organik fazlarla da sürmüştür. Dağılım katsayıları, organik fazdaki modifiye edici yüzdesi ve amin derişiminin artışı ile birlikte yükselmiştir. Yükleme oranı değerlerinin özellikle çözücü türünden etkilendiği gözlemlenmiştir.

Journal of Bioscience and Bioengineering, 2016