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Öğe A sustainable approach for xylitol production from pistachio shell using Candida tropicalis(Wiley, 2025) Hazal, Filiz; Ozbek, Hatice Neval; Yilmaztekin, Murat; Gogus, Fahrettin; Yanik, Derya KocakThis study presents a novel approach for producing xylitol from xylose-rich hydrolysate derived from pistachio shells. Initially, xylose-rich hydrolysate was obtained through microwave-assisted high-pressure CO2/H2O hydrolysis, achieving a maximum xylose concentration of 14.58 +/- 0.11 g L-1 and yield of 62.01 +/- 0.92% (w w-1). Prior to the bioconversion process, the hydrolysate was detoxified using activated charcoal to remove inhibitory compounds such as hydroxymethylfurfural (HMF) and furfural. Xylitol production from the detoxified hydrolysate was carried out biotechnologically using the yeast Candida tropicalis. A Box-Behnken design was implemented to investigate the effect of temperature, pH, and aeration rate on xylitol yield during bioconversion in bioreactor. The highest xylitol yield of 0.94 g g-1 was recorded at 72 h under optimized conditions of 34.5 degrees C, pH 4.5, and 1.2 vvm. Recovery and purification of xylitol from the fermentation medium was achieved using ethanol as an antisolvent. Xylitol was recovered with a yield of 68.4% from culture medium by crystallization. Based on the findings of this study, a sustainable and environmentally friendly process can be proposed for recovering and purifying xylitol from pistachio shell hydrolysate.Öğe Adsorption and desorption characteristics of epigallocatechin-3-gallate from discarded green tea leaves on macroporous resin(Springer Int Publ Ag, 2025) Bilcanoglu Cagan, Basak; Karakaya, Huseyin; Yilmaztekin, MuratGreen tea (Camellia sinensis) is intensely consumed all over the world and tea leaves discarded from production are a rich source of catechins, especially epigallocatechin-3-gallate (EGCG). This study aimed to perform preparative separation of EGCG from green tea waste by using macroporous resin and to reveal adsorption and desorption characteristics. Nine types of resins were compared for their adsorption and desorption capacities and desorption rate of EGCG, and NKA-2 was found the most suitable resin for the purpose. Adsorption isotherms were evaluated at 25 degrees C, 35 degrees C and 45 degrees C. Experimental data were well described with pseudo-second-order kinetics model and fitted best to the Langmuir model in tested temperatures. In dynamic separation process, 83% of adsorbed EGCG was recovered from the resin by using 70% ethanol. It has been thought that using macroporous resin can be an effective way of EGCG separation from green tea waste for commercial purposes. [Graphical abstract]Öğe Analysis of Volatile Components of Cape Gooseberry (Physalis peruviana L.) Grown in Turkey by HS-SPME and GC-MS(Hindawi Ltd, 2014) Yilmaztekin, MuratVolatile components in cape gooseberry fruit at ripe stage were collected using headspace-solid phase microextraction, and analyzed by gas chromatography-mass spectrometry. Three solid phase microextraction fiber coatings (DVB/CAR/PDMS, CAR/PDMS, and PDMS/DVB) were tested for evaluation of volatile compounds. DVB/CAR/PDMS fiber showed a strong extraction capacity for volatile compounds and produced the best result in case of total peak areas. A total of 133 volatile compounds were identified in fruit pulp; among them 1-hexanol (6.86%), eucalyptol (6.66%), ethyl butanoate (6.47%), ethyl octanoate (4.01%), ethyl decanoate (3.39%), 4-terpineol (3.27%), and 2-methyl-1-butanol (3.10%) were the major components in the sample extracts.Öğe Antimicrobial and Herbicidal Activities of the Essential Oil from the Mediterranean Thymus eigii(Taylor & Francis Ltd, 2018) Ulukanli, Zeynep; Cenet, Menderes; Ince, Huseyin; Yilmaztekin, MuratEssential oil (EO) of Thymus eigii (Lamiaceae) was hydrodistillated and characterized using with GC/MS. Forty-three constituents were determined accounting 100 % of the EO. The predominant constituents were thymol (24.77 %), carvacrol (14.00 %), p-cymene (10.91 %), -terpinene (6.53 %) and borneol (6.48 %). EO showed different levels of antimicrobial activities on test microorganisms. C. albicans, C. parapsilosis and S. aureus ATCC 29213 had the MIC/MFC/MBC values with 0.07/0.18 mg/ml, 0.18/0.36 mg/ml and 0.36/1.22 mg/ml respectively. EO of T. eigii exhibited pronounced herbicidal activities by inhibiting the germination and the growth of the seedlings of all plant species.Öğe Bioactive properties of powdered peppermint and spearmint extracts: Inhibition of key enzymes linked to hypertension and type 2 diabetes(Elsevier, 2020) Cam, Mustafa; Basyigit, Bulent; Alasalvar, Hamza; Yilmaztekin, Murat; Ahhmed, Abdulatef; Sagdic, Osman; Konca, YusufPeppermint and spearmint, both members of the Lamiaceae family, have been used in the form of extracts, infusions, and decoctions, because of their health benefits. Consumers are looking for functional food products which not only provide health benefits but also necessitate less preparation time. Therefore, this study aimed to investigate the bioactive properties of powdered peppermint and spearmint extracts. Peppermint and spearmint extracts obtained using pressurized water extraction were made into powder forms with a spray dryer using the air inlet temperature of 140 degrees C. Powdered peppermint extract (PPE) and powdered spearmint extract (PSE) showed significant inhibition against key enzymes of type 2 diabetes (alpha-glucosidase) and hypertension (angiotensin 1-converting enzyme, ACE). Alpha glucosidase inhibition degree of PPE and PSE as IC50 values was 0.6 and 1.2 mg/mL, respectively, while IC50 values for the ACE inhibition test were 4.5 mg for PPE and 5.8 mg for PSE. The HPLC-DAD method for ACE inhibition activity showed the suitability of this method for plant extracts high in phenolics which had no interference effects on the results. There were no differences between PPE and PSE in the DPPH test. However, PPE had higher Trolox equivalent antioxidant capacity (190 mg/g) with the ABTS test than PSE (170 mg/g). The predominant phenolics of PPE and PSE were found to be eriocitrin (47 mg/g) and rosmarinic acid (27 mg/g), respectively.Öğe Changes in Volatile Compounds and Some Physicochemical Properties of European Cranberrybush (Viburnum opulus L.) During Ripening Through Traditional Fermentation(Wiley, 2015) Yilmaztekin, Murat; Sislioglu, KubraThe changes in volatile compounds and some physicochemical properties of European Cranberrybush (Viburnum opulus L.) were investigated during traditional fermentation. Using the principal component analysis (PCA), relations between volatile compounds and fermentation were associated with dynamics of these compounds. In total, 58 volatile compounds were identified, 3-methylbutanoic acid (25.4% to 66.4% of identified volatile compounds) being the major constituent in raw, 2-, 3-, and 4-mo fermented European Cranberrybush fruits, while 2-octanone was dominant in 1-mo fermented sample with a 30% of the total identified volatiles. The amount of total volatile compounds was increased in the 1st month of fermentation and then decreased gradually in the following months. Acids were the dominant volatile compounds in raw and 3- to 4-mo fermented European Cranberrybush. Ketones and alcohols had the highest percentage in total volatile compounds in the 2nd and 3rd months of fermentation, respectively. Practical Application The fermented fruit juice of European cranberrybush is a traditional drink consumed by people living in middle Anatolian region. It has an astringent taste and the length of the traditional fermentation is important to mask the astringency and obtain a more pleasant taste. This study has reported the changes in volatile compounds of fruits during the fermentation. The results demonstrated that the length of fermentation affects the volatile composition of fruits significantly. The identification of the principal compounds produced during the fermentation can be of help in searching for indicators of off-flavor and in deciding when to stop the fermentation process to avoid production of off-flavor compounds.Öğe Characterisation of peppermint (Mentha piperita L.) essential oil encapsulates(Taylor & Francis Ltd, 2019) Yilmaztekin, Murat; Levic, Steva; Kalusevic, Ana; Cam, Mustafa; Bugarski, Branko; Rakic, Vesna; Pavlovic, VladimirAim: The aim was to choose the optimal encapsulation system and to incorporate encapsulates loaded with essential oil into the ice cream as a model food product. Methods: Ca-alginate beads were produced by electrostatic extrusion process. Gelatine/alginate coacervates were processed with coacervation. Carnauba wax microparticles were produced using melt dispersion process. Morphological properties, chemical, and thermal stabilities of encapsulates were tested by SEM, FTIR spectral, and thermogravimetric analysis. Results: Alginate provided sufficient emulsion stability over 1 h. Ca-alginate showed higher encapsulation efficiency (EE) (98.4 +/- 4.3%) compared to carnauba wax (94.2 +/- 7.8%) and gelatine/alginate coacervates (13.2 +/- 1.2%). The presence of essential oil in all three types of encapsulates confirmed with FTIR. The encapsulation process ensured controlled release and thermal stability of the oil. Conclusions: Ca-alginate matrix as the most suitable for peppermint essential oil encapsulation. The sensory analysis showed that ice cream incorporating encapsulates is a promising system for the consumption of health beneficial peppermint essential oil.Öğe CHARACTERIZATION OF POTENT AROMA COMPOUNDS OF CAPE GOOSEBERRY (PHYSALIS PERUVIANA L.) FRUITS GROWN IN ANTALYA THROUGH THE DETERMINATION OF ODOR ACTIVITY VALUES(Taylor & Francis Inc, 2014) Yilmaztekin, MuratThis article presents the investigation of the aroma profile of cape gooseberry (Physalis peruviana L.) grown in Antalya, Turkey. The analyses were carried out by means of liquid-liquid extraction followed by gas chromatography-flame ionization detection and gas chromatography-mass spectrometry for quantification and identification, respectively. Sensory analysis confirmed that the organic extract obtained by liquid-liquid extraction was representative of cape gooseberry odor. A total of 83 volatile compounds were identified and quantified in fruit pulp, including 23 esters, 21 alcohols, 11 terpenes, 8 ketones, 8 acids, 6 lactones, 4 aldehydes, and 2 miscellaneous. The main aroma components of the cape gooseberry (concentration >3%) were -hexalactone (17.66%), benzyl alcohol (17.22%), dimethylvinylcarbinol (6.54%), 1-butanol (5.71%), 2-methyl-1-butanol (5.22%), cuminol (3.98%), -octalactone (3.64%), and 1-hexanol (3.25%). The calculated odor activity values suggest that -octalactone, -hexalactone, ethyl octanoate, 2-heptanone, nonanal, hexanal, citronellol, 2-methyl-1-butanol, benzyl alcohol, phenethyl alcohol, 1-heptanol, ethyl decanoate, and 1-butanol were the potent aroma compounds of cape gooseberry. Within these, -octalactone (OAV: 46.9) was the most powerful contributor to the aroma of the fruit. It was concluded that cape gooseberry has characteristic indicator odorants that contribute to the overall aroma, which also can be used as quality-freshness markers of this fruit.Öğe A comparative melissopalynological study of royal jelly from Turkey(Taylor & Francis As, 2022) Yil, Gulsah; Karlidag, Semiramis; Akyol, Abuzer; Koseman, Abdurrahman; Yilmaztekin, Murat; Erdogan, Selim; Seker, IbrahimThree treatments (Glucose, Sucrose, Bee Feed Syrup) were used to examine the influence of supplementary feeding on the pollen spectrum of the royal jelly produced by Apis mellifera L. colonies. Apis mellifera colonies were located in the Battalgazi and Dogansehir districts of Malatya province in Turkey. In total 255 royal jelly samples were investigated and the analysis recorded over 30 taxa. In both sites the control group heavily utilised Quercus, Verbascum, Astragalus, and Lamiaceae. The feeding treatments saw Quercus, Verbascum, and Astragalus still being used but in different proportions. The utilisation of Lamiaceae was much reduced and Echium became an important component in colonies that had supplementary feeding.Öğe Confirmatory Method for the Determination of Volatile Congeners and Methanol in Turkish Raid According to European Union Regulation (EEC) No. 2000R2870: Single-Laboratory Validation(Aoac Int, 2011) Yilmaztekin, Murat; Cabaroglu, TurgutA method described by European Union Regulation (EEC) No. 2000R2870 was validated and supported by GC/MS analysis for the determination of volatile congeners and methanol in Turkish raki. The method was validated in terms of specificity, accuracy, precision, LOD, LOQ, linearity, and robustness. The specificity of the method was demonstrated, and the method showed excellent accuracy (97.5-100.1%). Linearity was checked in the ranges of 0.200-26.390 mg/100 mL for more volatile compounds and 1.155-48.00 mg/100 mL for less volatile compounds, after concentrations found in Turkish raki were taken into account. The calibration curves of all analytes showed good linearity (R-2 > 0.998). The within- and between-day precision (RSD) values of 11 analytes were in the range. of 0.18-4.50%. The LOD and LOQ values were in the range of 0.014-0.362 and 0.045-1.085 mg/100 mL, respectively. The method can be used as an absolute quantification method for the determination of volatile congeners and methanol in Turk ish raki and for QC.Öğe Effect of Maceration Time on Free and Bound Volatiles of Red Wines from cv. Karaoglan (Vitis vinifera L.) Grapes Grown in Arapgir, Turkey(Wiley, 2015) Yilmaztekin, Murat; Kocabey, Nimet; Hayaloglu, Ali AdnanSkin maceration is an essential winemaking technique that affects sensory properties and aroma of red wines. The aim of this study was to investigate aroma profiles of red wines made from cv. Karaoglan, a grape variety grown in Arapgir (Malatya, Turkey) and the effect of maceration time (5, 10, and 15 d) on free and bound aroma compounds and sensory properties. Three maceration times were applied in durations of 5, 10, and 15 d. Free and glycosidically bound aroma compounds were analyzed using gas chromatography-mass spectrometry (GC-MS) in Karaoglan wines, and the effect of different maceration times on aroma composition were evaluated. Results indicate that extended maceration time significantly influenced the aroma composition of wines both qualitatively and quantitatively. A total of 59 free and 22 bound aroma compounds were identified in the final wines. The maximum of free aroma content was achieved with 5 d of maceration, while 15 d of maceration gave the highest amount of glycosidically bound aroma compounds. From sensorial point of view, the wine produced with 10 d of maceration had the best panel score compared to wines with 5 and 15 d of maceration. This is the first study referring to the composition of aroma compounds of red wines made from cv. Karaoglan. It was concluded that this cultivar resulted in a good quality wine in terms of bound and free aroma compounds. This information of vinification practices that influence the chemical properties of wine is useful for grape growers and winemakers.Öğe The effect of temperature and aeration on ethyl acetate production by Pichia yeasts(Elsevier Sci Ltd, 2011) Yilmaztekin, Murat; Cabaroglu, Turgut; Erten, Huseyin[Abstract Not Available]Öğe Effects of Fermentation Temperature and Aeration on Production of Natural Isoamyl Acetate by Williopsis saturnus var. saturnus(Hindawi Ltd, 2013) Yilmaztekin, Murat; Cabaroglu, Turgut; Erten, HuseyinIsoamyl acetate is a natural flavour ester, widely used as a source of banana flavour by the food industry. Williopsis saturnus var. saturnus is a yeast which can produce isoamyl acetate by esterification of amyl alcohols with acetyl coenzyme A via fermentation. The evaluation of this kind of production as an alternative way to obtain natural banana flavour could be possible, if the levels produced were high enough to make a commercial product. In this study, the effects of temperature (15 degrees C and 25 degrees C) and aeration (aerobic, semiaerobic, and anaerobic) on the production of isoamyl acetate by Williopsis saturnus var. saturnus from sugar beet molasses were examined. According to the results obtained, isoamyl acetate production rate and specific productivity were higher at 25 degrees C than at 15 degrees C and at semiaerobic condition than aerobic and anaerobic conditions. Williopsis saturnus var. saturnus showed a production rate of 0.703 mg L-1 h(-1) and a specific productivity of 0.0297 mg L-1 cell(-1) h(-1) isoamyl acetate with semiaerobic condition at 25 degrees C. The maximum amount of isoamyl acetate reached with these conditions was 118 mg/L.Öğe Essential Oil Constituents of Tanacetum cilicicum: Antimicrobial and Phytotoxic Activities(Wiley-Hindawi, 2017) Ulukanli, Zeynep; Demirci, Salih; Yilmaztekin, MuratAerial parts of Tanacetum cilicicum were hydrodistillated for 3 h using Clevenger. Essential oil (EO) yield was 0.4% (v/w). According to the GC/MS analyses, EO of T. cilicicum consisted of monoterpenes [alpha-pinene (2.95 +/- 0.19%), sabinene (2.32 +/- 0.11%), and limonene (3.17 +/- 0.25)], oxygenated monoterpenes [eucalyptol (5.08 +/- 0.32%), camphor (3.53 +/- 0.27%), linalool (7.01 +/- 0.32%),alpha-terpineol (3.13 +/- 0.23%), and borneol (4.21 +/- 0.17%)], and sesquiterpenes [sesquisabinene hydrate (6.88 +/- 0.41%), nerolidol (4.90 +/- 0.33%),alpha-muurolol (4.57% alpha 0.35), spathulanol (2.98 alpha 0.12%), juniper camphor (2.68 alpha 0.19%), (-)-caryophyllene oxide (2.64 +/- 0.19%), 8-hydroxylinalool (2.62 +/- 0.15%), and A-cadinene (2.48 +/- 0.16%)]. In the antimicrobial assay, MIC/MBC values of the EO were the most significant on B. subtilis (0.39/0.78 mu L/mL) and B. cereus (0.78/1.56 mu L/mL). The most prominent phytotoxic activities of the EO were observed on L. sativa, L. sativum, and P. oleracea. The results of the present study indicated that EO of T. cilicicum includes various medicinally and industrially crucial phytoconstituents that could be in use for industrial applications. The finding of this study is the first report on this species from the East Mediterranean region.Öğe Essential oil constituents, antimicrobial and herbicidal assays of lesser calamint (Calamintha nepeta (L.) Savi subsp. nepeta) from East Mediterranean Region of Turkey(Amg Transcend Assoc, 2016) Ulukanli, Zeynep; Demirci, Salih Cercis; Yilmaztekin, MuratCalamintha nepeta (L.) Savi subsp. nepeta (Lamiaceae) has a widespread use in the mint family of the Angiosperms. Uses of the spectacular aromatic feature as well as immense medicinal properties of this species have been dated back to the antiquity in the Mediterranean life. Aerial parts of the Calamintha nepeta (L.) Savi subsp. nepeta were collected from the wild ecosystems of the Amanos Mountains (East Mediterranean of Turkey). The hydrodistillated essential oil (EO) of the species were predominantly rich in with the following constituents; pulegone (43.02%) and menthone (28.09%). EO of the tested species had also notable antimicrobial activities. Minimum Inhibitory and Bacterio/Fungio-Cidal Concentrations (MIC and MBC/MFC) of C. nepeta' EO were 0.39/0.78 mu l/ml for B. subtilis, 0.19/0.78 mu l/ml for C. albicans and 0.78/0.78 mu l/ml for C. parapsilosis. In the herbicidal assay, a 100% inhibition of the seed germination, radicle and plumule growth of L. sativa was found at 0.5, 1.0 and 2.0 mg/ml of the EO. The germination and seedling lengths of P. oleracea and L. sativum in response to 1.0 and 2.0 mg/ml of the EO treatment were the same as those found for L. sativa. Essential oil composition, antimicrobial as well as the herbicidal assays of the species from Amanos Mountans (East Mediterranean region of Turkey) could be regarded as the first report.Öğe Fruit Weight, Total Phenolics, Acidity and Sugar Content of Edible Wild Pear (Pyrus elaeagnifolia Pall.) Fruits(Springer, 2015) Yilmaz, Kadir Ugurtan; Ercisli, Sezai; Cam, Mustafa; Uzun, Aydin; Yilmaztekin, Murat; Kafkas, Ebru; Pinar, HasanWild pear (Pyrus eleagnifolia) is a naturally grown species mainly in inner Anatolia and its edible small fruits are traditionally consumed by local peoples and are called Ahlat in Turkey. Its seedlings are also used as rootstock for commercial pear cultivars. In this study, we reported first time pomological characteristics and biochemical compositions in fruits of a wide number selected wild pears genotypes (Pyrus eleagnifolia Pall.) from inner Anatolia. The obtained results revealed that there were significant differences among wild pear genotypes for all analyzed parameters. Fruit weight, total phenolics, total acidity and total sugar contents of the fruits varied from 4.71 to 27.09 g, 42.79 to 119.14 mg GAE/100 g, 0.20 to 1.40 g/100 g and 8.36 to 19.31 g/100 g, respectively. Considering these values, it was concluded that naturally grown wild pears of Anatolia with their rich salubrious biochemical compounds could reliably be used as a food source for humans.Öğe Macroporous adsorbents for in situ removal of flavours produced biotechnologically(Elsevier Science Bv, 2012) Yilmaztekin, Murat[Abstract Not Available]Öğe Methanol and Major Volatile Compounds of Turkish Raki and Effect of Distillate Source(Inst Brewing, 2011) Cabaroglu, Turgut; Yilmaztekin, MuratTurkish Raki is the traditional anise flavoured distillate beverage produced mainly from a grape distillate called suma. Two types of Raid are produced in Turkey according to the distillate source. They are Type I - a fresh grape Raki produced only from suma and Type II - a Raki produced from a blended distillate of suma and alcohol of agricultural origin (mainly molasses). In this study the content of ethanol, methanol, distillate based major volatile compounds (aldehydes, esters, higher alcohols), aniseed based anethole and estragole, volatile acid and sugar values in two types of commercial Raki samples (40 samples) was determined and the effect of distillate source on the composition was examined. The distillate and the aniseed based major compounds of the Raki samples were analysed by direct injection with a GC-MS-FID according to the European Commission Reference Method. The results of variance analysis and PCA showed that there was a significant difference between the two types of Raid samples. Total volatiles (esters and higher alcohols), methanol, trans-anethole, estragole and sugar values were higher in the samples made from suma alone. All of the analysed component levels of the Turkish Raki samples were in compliance with Turkish Distilled Beverage Regulations. The methanol levels ranged between 28.00-50.87 g/hL absolute alcohol (AA) in Type I samples and 22.03-41.06 g/hL AA in Type II samples. Distillate based total volatiles levels ranged between 136.12-147.88 g/hL AA, with a mean value of 142.88 g/hL AA, in Type I samples and 102.44-113.45 g/hL, with a mean value of 107.9 g/hL, in the Type II samples. The anise based compound trans-anethole levels were significantly higher in the Type I samples (1,298-1,570 mg/L) than in the Type 11 samples (1,014-1,199 mg/L). According to distillate based volatiles, the Turkish Raid has a valuable content of volatile substances compared to other anise flavoured spirits.Öğe MW-HPCO2 sistemi ile elde edilen antep fıstığı kabuğu hidrolizatından Candida tropicalis 13803 kullanılarak ksilitol biyoüretimi(2024) Yilmaztekin, Murat; Gogus, Fahrettin; Özbek, Hatice Neval; Yanik, Derya Kocak; Hazal, FilizAmaç: İkincil tarımsal kalıntılardan biyoteknolojik yolla ksilitol üretimi, sürdürülebilir ve çevresel bir amaç için umut verici bir yaklaşımdır. Lignoselülozik biyokütle, biyoyakıt ve biyokimyasal üretim için önemli bir hammaddedir. Erişilebilirliği, maliyet etkinliği, yenilenebilirliği ve çevre dostu olması onu fosil yakıtlara ve diğer geleneksel enerji ve kimyasal kaynaklarına karşı cazip bir alternatif haline getirmektedir. Materyal ve yöntem: Bu çalışmada, Antep fıstığı kabuğundaki ksilanın ksiloza dönüşümü, yeni bir teknoloji olan mikrodalga destekli yüksek basınçlı CO2/H2O ile sağlanmıştır. Ksiloz bakımından zengin Antep fıstığı kabuğu hidrolizatı, ksilitol üretimi için Candida tropicalis ATCC 13803 tarafından kullanılmıştır. Erlenmayerde ksilitol üretimi için farklı ksiloz konsantrasyonları (50, 100 ve 150 g/L) kullanılmıştır. Tartışma ve sonuç: HMF ve furfural, aktif kömür ile ksiloz bakımından zengin hidrolizattan tamamen uzaklaştırılmıştır. Maya performansındaki iyileşme, ksiloz konsantrasyonunun artması ile kısıtlanmıştır. Erlenmayerde fıstık kabuğu hidrolizatı kullanılarak C. tropicalis tarafından üretilen en yüksek ksilitol (65,15 g/L) ve 0,66 g/g maksimum verim 100 g/L ksiloz konsantrasyonu ile elde edilirken, 50 g/L ve 150 g/L ksiloz ile üretilen ksilitol sırasıyla 0,65 ve 0,37 g/g bulunmuştur. Hacimsel verimlilik 100 g/L ksilozda, 50 g/L ve 150 g/L ksiloz konsantrasyonlarına kıyasla sırasıyla 1,28 kat ve 1,84 kat daha yüksek bulunmuştur. Detoksifiye edilmiş fıstık kabuğu hidrolizatının 100 g/L ksilozdaki ksilitol üretim performansı (71,73 g/L) saf ksiloz ile neredeyse aynı bulunmuştur. Ancak, maya 150 g/L'de ksilozu tüketememiş ve ksilitol üretimi gerçekleşmemiştir.Öğe Natural Vanillin Production from Isoeugenol by Using Pseudomonas putida in Biphasic Bioconversion Medium(Galenos Publ House, 2022) Karakaya, Huseyin; Yilmaztekin, MuratVanillin, is one of the most demanded flavoring agents in the world. Because of insufficient supply of natural vanillin, market demand is usually supplied by synthetic ones. In this study, it was investigated possibility of usage biphasic system in bioconversion of isoeugenol to vanillin by Pseudomonas putida (HUT 8100). Organic phase was composed of isoeugenol while biocatalyst, P. putida culture, was dispersed in aqueous phosphate solution. Isoeugenol was used as sole carbon source in concentrations ranging between 50-600 g L-1. Incubation was performed at 28 degrees C, at pH 6.3 and 180 rpm shaking. Effect of initial substrate concentration and bioconversion time were investigated. Isoeugenol and vanillin amounts in medium were simultaneously analyzed in HPLC system. After 120 h incubation, vanillin reached the its highest level when 400 g L-1 isoeugenol was applied in medium. In specified conditions, it was achieved to produce 11.95 g L-1 vanillin with 6.2% molar yield within 15 days of bioconversion. It is thought that, obtained result by using biphasic system is very important for the industrial applications in production of natural vanillin via bioconversion.
