Food Engineering / Gıda Mühendisliği
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Article Effect of Substrate Concentration and Scale Up on the Polygalacturonase Production(Gıda Teknolojisi Derneği, 2019) Göğüş, Nihan; Tarı, CananPectinases have been used for many industrial applications since long time ago. The largest industrial application of these enzymes is in fruit juice and wine production for the extraction, filtration and clarification and for the maceration of fruits and vegetables. They work by enzymatic breaking down of the cell wall.In this study it was aimed to use the previously optimized shake flask media formulation in batch mode 1 L scale serial bioreactor system and 5 L scale in order to investigate the effects of substrate concentration and scale on PG activity and biomass production. In conclusion it was observed that average PG activity (101.29 U/ml) obtained in 5L scale bioreactor experiments was higher than the maximum PG activity (88.55 U/ml) at 40 g/L orange peel (OP) concentration obtained in the 1 L scale substrate concentration experiment. Furthermore,PG activity increased with an increase in substrate concentration except for 60 g/L orange peel concentration.Article Citation - WoS: 69Citation - Scopus: 89Pectinase Enzyme-Complex Production by Aspergillus Spp. in Solid-State Fermentation: a Comparative Study(Elsevier, 2012) Heerd, Doreen; Yeğin, Sırma; Tarı, Canan; Fernandez Lahore, MarceloA comparative evaluation of three Aspergillus species according to their pectinase production in solid-state fermentation was performed. Solid-state fermentation offers several potential advantages for enzyme production by fungal strains. Utilization of agricultural by-products as low-cost substrates for microbial enzyme production resulted in an economical and promising process. The pectinolytic enzyme activities of two Aspergillus sojae strains were compared to a known producer, Aspergillus niger IMI 91881, and to A. sojae ATCC 20235, which was re-classified as Aspergillus oryzae. Evaluation of polymethylgalacturonase and polygalacturonase activity was performed as well as exo- vs. endo-enzyme activity in the crude pectinase enzyme-complex of the mentioned strains. Furthermore, a plate diffusion assay was applied to determine the presence and action of proteases in the crude extracts. A. sojae ATCC 20235 with highest polymethylgalacturonase activity and highest polygalacturonase activity both exo- and endo-enzyme activity, is a promising candidate for industrial pectinase production, a group of enzymes with high commercial value, in solid-state fermentation processes. Beside the enzymatic assays a protein profile of each strain is given by SDS-PAGE electrophoresis and in addition species-specific zymograms for pectinolytic enzymes were observed, revealing the differences in protein pattern of the A. sojae strains to the re-classified A. oryzae. (C) 2011 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.Article The Relationship of Pellet Morphology To Polygalacturonase Production of Rhizopus Oryzae in Various Media Compositions(Gıda Teknolojisi Derneği, 2011) Tarı, Canan; Özkan, Kamer; Oncu, Şelale; Avcı, TubaBu çalışmada, ortam kompozisyonunu belirleyen değişik faktörlerin Rhizopus oryzae pellet morfolojisine ve poligalakturonaz (PG) enzimi üretimine olan etkisi incelenmiştir. En yüksek PG aktivitesine (11.53 U/ml) 4 mg/kg Zn+2 içeren, Mg+2 içermeyen ve pH 3 olan basal ortamında ulaşılmıştır. Karbon kaynağı olarak 14.78 g/l glukoz, 10 g/l galaktoz, 5 g/l mannoz, 0.5 g/l arabinoz ve 19.73 g/l ksilozun birlikte kullanılmıyla da en yüksek PG aktivitesine (27.94 U/ml) ulaşılmıştır. Mısır unu nitrojen kaynağı olarak PG sentezini tetiklemede oldukça etkili olup bir diğer yüksek tetikleyici olan mısır maserasyon sıvısı (CSL) ve $(NH _4)2SO _4$’den %33 daha fazla aktivite vermiştir. $(NH _4)2SO _4$ and 25 g/l glukoz içereren formulasyon ortalama çapı 1.25± 0.25 olan en fazla sayıda pellet oluşumunu sağlamıştır. Ortalama çapı 1.75±0.25 mm olan pelletlerin oluşumu ise yüksek glukoz konsantrasyonuna sahip (50g/l) maya ekstraktı içeren formulasyon ile elde edilmiştir. Uygun karbon kaynağının (glukoz) uygun nitrojen kaynağı (mısır unu) ile interaktif etkisi PG aktivitesini basal ortama göre 4 kat daha arttırmış, ortalama çapı 1.44±0.35mm olan pelletler oluşturmuştur.Article Aspergillus Sojae Tarafından Üretilen Poligalakturonazın Kısmi Saflaştırılması için Kromatografik Bir Yaklaşım(Sidas Medya Ajans Tanıtım Danışmanlık Ltd. Şti., 2017) Şen, İlknur; Mata-Gomez, Marco A.; Palomares, Marco Rito; Tarı, Canan; Dinç, MelikeBu çalışmanın amacı, A. sojae mutantından poligalakturonaz üretilmesi ve ham ekstraktın kromatografik yöntemlerle kısmi saflaştırılmasıdır. Peptitlerin konfirmasyonu için ilk basamak olarak, jel içinde sindirilmiş sodyum-dodesil-sülfatpoliakrilamid-jel-elektroforezi (SDS-PAGE) jellerinde matriks-yardımlı lazer desorpsiyon/iyonlaştırmalı-uçuş zamanlıkütle spektrometresi (Maldi-TOF MS) analizi yapılmıştır. Poligalakturonaz üretimi için, katı-faz ve derin fermentasyonlarda üç farklı karbon kaynağı kullanılmıştır. Ham ekstrakt ilk olarak iyon değişim kromatografisi (IEXC) ile saflaştırılmıştır ve ardından bunu boyut eleme kromatografisi izlemiştir. Derin [acı portakal kabuğu, şeker pancarı melası ve (NH4)2SO4] ve katı-faz (buğday kepeği, şeker pancarı ve HCl) fermentasyonlarından elde edilen ham ekstraktlar yüksek seviyede poligalakturonaz enzim aktivitesi (sırasıyla 95.22 and 50.27 U/mL) göstermiştir. IEXC toplanmış fraksiyonunun (180, 200 ve 220 mM tuz fraksiyonları) boyut elemesi, en yüksek verimi (%36) ve saflaştırma katını (2.00) göstermiştir. SDS-PAGE'den elde edilen olası poligalakturonaz bantları jel içinde sindirilmiş ve peptit konfirmasyonu için Maldi-TOF-MS ile analiz edilmiştir.Article Tarıma Dayalı Sanayi Atıklarının Katı Kültür Fermantasyonu ile Değerlendirilmesi: Sürece Etki Eden Faktörlere Genel Bakış(Gıda Teknolojisi Derneği, 2015) Demir, Hande; Tarı, CananKatı-kültür fermantasyonu (KKF) batı ülkelerinin son yıllarda ilgisini çekmiş olan fakat doğu ülkeleri tarafından çok eski zamanlardan beri kullanılagelen bir teknolojidir. KKF, mühendislik ve çevresel açıdan bakıldığında birçok ürün ve biyolojik işlemin gelişimi için uygun bir yöntem olmakla birlikte, hâlihazırda derin kültür fermantasyonu ile rekabeti devam etmektedir. Bu derleme makalede KKF’nin tanımı, kısa tarihçesi, tarıma dayalı sanayi atık kullanımının avantajları ve kısıtları ile birlikte inert yataklar hakkında bilgi verilmektedir. Derlemenin önemli bir bölümünde ise inokülüm oranı, inkübasyon süre ve sıcaklığı, nem içeriği ve su aktivitesi, başlangıç pH’ı, parçacık büyüklüğü, karıştırma ve inokülüm türü gibi KKF işlemlerini etkileyen etkenler özetlenmiştir. Her bir etkenin KKF işlemleri üzerindeki etkisi teorik olarak detaylandırılmakla kalmayıp, aynı zamanda literatürde yer alan çalışmalar yardımıyla da tartışılmıştır. Bu makale KKF işlemleriyle ilgilenen araştırmacılara ışık tutacağı gibi tarıma dayalı sanayi atıklarına katma değer kazandırılması konusunda da üreticilere yol gösterecektir.Article Citation - WoS: 18Citation - Scopus: 35Microparticle-Enhanced Polygalacturonase Production by Wild Type Aspergillus Sojae(Springer Verlag, 2017) Karahalil, Ercan; Demirel, Fadime; Evcan, Ezgi; Germeç, Mustafa; Tarı, Canan; Turhan, İrfanPolygalacturonases (PGs), an important industrial enzyme group classified under depolymerases, catalyze the hydrolytic cleavage of the polygalacturonic acid chain through the introduction of water across the oxygen bridge. In order to produce and increase the concentration of this enzyme group in fermentation processes, a new approach called microparticle cultivation, a promising and remarkable method, has been used. The aim of this study was to increase the PG activity of Aspergillus sojae using aluminum oxide (Al2O3) as microparticles in shake flask fermentation medium. Results indicated that the highest PG activity of 34.55 ± 0.5 U/ml was achieved with the addition of 20 g/L of Al2O3 while the lowest activity of 15.20 ± 0.2 U/mL was obtained in the presence of 0.1 g/L of Al2O3. In fermentation without microparticles as control, the activity was 15.64 ± 3.3 U/mL. Results showed that the maximum PG activity was 2.2-fold higher than control. Additionally, smaller pellets formed with the addition of Al2O3 where the lowest pellet diameter was 955.1 µm when 10 g/L of the microparticle was used. Also, it was noticed that biomass concentration gradually increased with increasing microparticle concentration in the fermentation media. Consequently, the PG activity was significantly increased in microparticle-enhanced shake flask fermentation. In fact, these promising preliminary data can be of significance to improve the enzyme activity in large-scale bioreactors.Article Citation - WoS: 1Citation - Scopus: 2Partial Purification of a Polygalacturonase From a New Aspergillus Sojae Mutant and Its Application in Grape Mash Maceration(John Wiley and Sons Inc., 2017) Yıldız, Semanur; Mata-Gomez, Marco A.; Tarı, Canan; Rito-Palomares, MarcoThe use of polygalacturonase (PG) preparations in winemaking promotes the release of phenolic compounds. A PG from a new source, Aspergillus sojae mutant, was semi-purified and tested for grape mash maceration. Crude extract (CE), a commercial pectinase, and two high PG activity semi-purified preparations, FI and FII , were applied for maceration at PG activity of 3.5 U g−1 of grape for 46 h. Enzyme-assisted maceration significantly (P < 0.05) increased the total phenolic content from 255.8 to 916.3 ± 5.2, 5732.9 ± 9.9, 563.4 ± 6.7 and 620.6 ± 18.4 mg L−1 for CE, commercial pectinase, FI and FII, respectively. The content of individual phenolics such as gallic, protocatechuic, chlorogenic and p-coumaric acids was improved. Principal component and hierarchical clustering analyses suggested that CE has a better performance upon the release of phenols. Semi-purified preparations acted similar to commercial pectinase. These findings open an opportunity for the potential use of PG from the mutant strain as an alternative macerating enzyme.Article Citation - WoS: 18Citation - Scopus: 19Control of Agitation Rate and Aeration for Enhanced Polygalacturonase Production in Submerged Fermentation by Aspergillus Sojae Using Agro-Industrial Wastes(John Wiley and Sons Inc., 2017) Fratebianchi, Dante; Crespo, Juan Manuel; Tarı, Canan; Cavalitto, SebastianBACKGROUND: The koji mold Aspergillus sojae, an industrially important microorganism, can produce high levels of pectinases utilizing agro-industrial wastes. This study introduces apricot and peach pomace, two agro-industrial wastes barely considered as raw material for the generation of value-added products, and focuses on its utilization together with orange peel for polygalacturonase production in submerged cultures using A. sojae. RESULTS: A Doehlert response surface methodology design conducted in shake flasks and applied individually with these three by-products led to 60–80 U mL−1 polygalacturonase activity. In bioreactor studies performed with a mixture of apricot pomace and orange peel, by fixing stirrer speed to 600 rpm and cascading airflow to the dissolved oxygen tension up to 1.7 vvm, oxygen limitation problems were overcome and polygalacturonase activity values of 380 U mL−1 were achieved. CONCLUSION: A simple and efficient strategy to minimize oxygen limitation with the lowest possible shear stress is provided for stirred-tank bioreactors working with highly viscous broths, so as to ultimately enhance microbial enzyme production. The polygalacturonase activity yields obtained in our study are among the highest reported in the literature.Article Citation - WoS: 10Citation - Scopus: 11Synthesis of Adsorbents With Dendronic Structures for Protein Hydrophobic Interaction Chromatography(Elsevier Ltd., 2016) Mata-Gomez, Marco A.; Yaman, Sena; Valencia-Gallegos, Jesus A.; Tarı, Canan; Rito-Palomares, Marco; Gonzalez-Valdez, JoseHere, we introduced a new technology based on the incorporation of dendrons-branched chemical structures-onto supports for synthesis of HIC adsorbents. In doing so we studied the synthesis and performance of these novel HIC dendron-based adsorbents. The adsorbents were synthesized in a facile two-step reaction. First, Sepharose 4FF (R) was chemically modified with polyester dendrons of different branching degrees i.e. third (G3) or fifth (G5) generations. Then, butyl-end valeric acid ligands were coupled to dendrons via ester bond formation. UV-vis spectrophotometry and FTIR analyses of the modified resins confirmed the presence of the dendrons and their ligands on them. Inclusion of dendrons allowed the increment of ligand density, 82.5 ± 11 and 175.6 ± 5.7 μmol ligand/mL resin for RG3 and RG5, respectively. Static adsorption capacity of modified resins was found to be ~60 mg BSA/mL resin. Interestingly, dynamic binding capacity was higher at high flow rates, 62.5 ± 0.8 and 58.0 ± 0.5 mg/mL for RG3 and RG5, respectively. RG3 was able to separate lipase, β-lactoglobulin and α-chymotrypsin selectively as well as fractionating of a whole proteome from yeast. This innovative technology will improve the existing HIC resin synthesis methods. It will also allow the reduction of the amount of adsorbent used in a chromatographic procedure and thus permit the use of smaller columns resulting in faster processes. Furthermore, this method could potentially be considered as a green technology since both, dendrons and ligands, are formed by ester bonds that are more biodegradable allowing the disposal of used resin waste in a more ecofriendly manner when compared to other exiting resins.Article Citation - WoS: 13Citation - Scopus: 18Effect of Physicochemical Parameters on the Polygalacturonase of an Aspergillus Sojae Mutant Using Wheat Bran, an Agro-Industrial Waste, Via Solid-State Fermentation(John Wiley and Sons Inc., 2016) Demir, Hande; Tarı, CananBACKGROUND: Polygalacturonases (PGs) are valuable enzymes of the food industry; therefore it is of great importance to discover new and GRAS PG-producing microbial strains. In this study, PG enzyme produced from a high PG activity producer mutant Aspergillus sojae using wheat bran at the flask scale under pre-optimized conditions of solid-state fermentation (SSF) was biochemically characterized. RESULTS: The crude PG enzyme showed optimum activity in the pH range 4.0–5.0 and was stable in the pH range 3.0–7.0. The optimum temperature for the PG was 40 °C and it retained 99% of its activity at 50 °C. The mutant A. sojae PG could preserve more than 50% of its stability between 25 and 50 °C, both for 30 and 60 min, and was found to be stable in the presence of most of the tested compounds and metal ions. The inactivation energy (Ed) was determined as 125.3 kJ mol−1. The enthalpy (ΔH*), free energy (ΔG*) and entropy (ΔS*) of inactivation were found to be stable with increasing temperature. CONCLUSION: The mutant A. sojae PG could be suitable for the clarification (depectinization) of orange and grape juices and wine. © 2015 Society of Chemical Industry.