Food Engineering / Gıda Mühendisliği
Permanent URI for this collectionhttps://hdl.handle.net/11147/12
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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 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: 3Citation - Scopus: 4Evaluation of Agro-Industrial Wastes, Their State, and Mixing Ratio for Maximum Polygalacturonase and Biomass Production in Submerged Fermentation(Taylor and Francis Ltd., 2015) Göğüş, Nihan; Evcan, Ezgi; Tarı, Canan; Cavalitto, Sebastian F.The potential of important agro-industrial wastes, apple pomace (AP) and orange peel (OP) as C sources, was investigated in the maximization of polygalacturonase (PG), an industrially significant enzyme, using an industrially important microorganism Aspergillus sojae. Factors such as various hydrolysis forms of the C sources (hydrolysed-AP, non-hydrolysed-AP, hydrolysed-AP + OP, non-hydrolysed-AP + OP) and N sources (ammonium sulphate and urea), and incubation time (4, 6, and 8 days) were screened. It was observed that maximum PG activity was achieved at a combination of non-hydrolysed-AP + OP and ammonium sulphate with eight days of incubation. For the pre-optimization study, ammonium sulphate concentration and the mixing ratios of AP + OP at different total C concentrations (9, 15, 21 g-1) were evaluated. The optimum conditions for the maximum PG production (144.96 ml-1) was found as 21 g-1 total carbohydrate concentration totally coming from OP at 15 g-1 ammonium sulphate concentration. On the other hand, 3:1 mixing ratio of OP + AP at 11.50 g-1 ammonium sulphate concentration also resulted in a considerable PG activity (115.73 ml-1). These results demonstrated that AP can be evaluated as an additional C source to OP for PG production, which in turn both can be alternative solutions for the elimination of the waste accumulation in the food industry with economical returns.Article Citation - WoS: 29Citation - Scopus: 29Microbial Strain Improvement for Enhanced Polygalacturonase Production by Aspergillus Sojae(Springer Verlag, 2014) Heerd, Doreen; Tarı, Canan; Fernandez Lahore, MarceloStrain improvement is a powerful tool in commercial development of microbial fermentation processes. Strains of Aspergillus sojae which were previously identified as polygalacturonase producers were subjected to the cost-effective mutagenesis and selection method, the so-called random screening. Physical (ultraviolet irradiation at 254 nm) and chemical mutagens (N-methyl-N′-nitro-N-nitrosoguanidine) were used in the development and implementation of a classical mutation and selection strategy for the improved production of pectic acid-degrading enzymes. Three mutation cycles of both mutagenic treatments and also the combination of them were performed to generate mutants descending from A. sojae ATCC 20235 and mutants of A. sojae CBS 100928. Pectinolytic enzyme production of the mutants was compared to their wild types in submerged and solid-state fermentation. Comparing both strains, higher pectinase activity was obtained by A. sojae ATCC 20235 and mutants thereof. The highest polygalacturonase activity (1,087.2±151.9 U/g) in solid-state culture was obtained by mutant M3, which was 1.7 times increased in comparison to the wild strain, A. sojae ATCC 20235. Additional, further mutation of mutant M3 for two more cycles of treatment by UV irradiation generated mutant DH56 with the highest polygalacturonase activity (98.8±8.7 U/mL) in submerged culture. This corresponded to 2.4-fold enhanced polygalacturonase production in comparison to the wild strain. The results of this study indicated the development of a classical mutation and selection strategy as a promising tool to improve pectinolytic enzyme production by both fungal strains.Article Citation - WoS: 13Citation - Scopus: 14Evaluation of Orange Peel, an Industrial Waste, for the Production of Aspergillus Sojae Polygalacturonase Considering Both Morphology and Rheology Effects(TUBITAK, 2014) Gögüş, Nihan; Hakgüder Taze, Bengi; Demir, Hande; Tarı, Canan; Ünlütürk, Sevcan; Lahore, Marcelo FernandezOrange peel is an agroindustrial waste rich in pectin and known to be an inducer for pectinase production. The use of this low-cost substrate for the production of an industrially important enzyme, polygalacturonase (PG), can be an alternative way to turn this waste into a value-added product, contributing to the reduction of environmental waste disposal problems. Enzyme productions by fungal microorganisms are affected by environmental and nutritional factors, demanding the determination of optimum conditions for maximum enzyme production with the desired fungal morphology and broth rheology. Therefore, complex and additional carbon sources were optimized with respect to PG production by Aspergillus sojae using statistical approaches. Effect of pH, another significant parameter affecting the rheology and morphology of the strain, was investigated in the serial bioreactor system using the optimized medium composition. Highest PG enzyme yield and productivity together with the maximum PG enzyme production (93.48 U/mL) were obtained under uncontrolled pH conditions. Under these conditions, morphologically, pellet sizes exhibited a normal distribution ranging between 0.5-1.0 mm and 1.0-1.5 mm, and rheological measurements revealed that fermentation broths showed non-Newtonian flow. The low pH trend observed during the course of the fermentation was another important positive outcome for industrial fermentations, prone to contamination problems.Article Citation - WoS: 48Citation - Scopus: 58Valorization of Wheat Bran for the Production of Polygalacturonase in Ssf of Aspergillus Sojae(Elsevier Ltd., 2014) Demir, Hande; Tarı, CananWheat bran, among various agro industrial by products, screened for the production of polygalacturonase (PG) in solid-state fermentation of Aspergillus sojae mutant strain, was found to be the most suitable substrate without the addition of any nutritive or inducing supplement. It was further characterized for its physicochemical composition and particle size distribution. The process conditions that favored the PG production using this substrate were determined as; 107 spore/g substrate inoculum concentration, 4 days of fermentation, 37°C of incubation temperature, 62% initial moisture content, water as the moistening agent, 100-250μm particle size of wheat bran, 3 times/day agitation and spore solution as the inoculum type which resulted into maximum PG activity of 535.4U/g substrate. Overall, this optimization process resulted in 7.3 and 3.9 fold of significant enhancement in the PG activity and productivity, respectively.Article Citation - WoS: 28Citation - Scopus: 32Optimization of the Process Parameters for the Utilization of Orange Peel To Produce Polygalacturonase by Solid-State Fermentation From an Aspergillus Sojae Mutant Strain(TUBITAK, 2012) Demir, Hande; Göğüş, Nihan; Tarı, Canan; Heerd, Doreen; Lahore, Marcelo FernandezThe effect of orange peel concentration, HCl concentration, incubation time and temperature, and inoculum size on the spore count and activity of polygalacturonase (PG) enzyme produced from Aspergillus sojae M3 by solidstate fermentation was screened using 2k factorial design. Orange peel and HCl concentrations and incubation time were significant factors affecting the responses. Optimum conditions favoring both PG and spore production from Aspergillus sojae M3 were determined as 2% orange peel and 50 mM HCl concentrations at 22 °C and 4.3 days of incubation. An overlay plot was constructed for use as a practical chart for production of high enzyme activity (>35.0 U/g substrate) and spore count (9.0 × 108 to 2.0 × 109 spore/mL) by superimposing the contours of PG activity and spore count responses. The accuracy and reliability of the constructed models on the responses was validated with the maximum calculated error rate between the predicted and actual activities at 14.1% and 22.4%, respectively. © TÜBİTAK.