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Öğe Downstream processes for plant cell and tissue culture(Springer-Verlag Berlin Heidelberg, 2013) Yesil-Celiktas O.; Vardar-Sukan F.Biotechnological cultivation of plant cells and tissues is one of the most challenging fields of recent scientific researches. The requirements of pharmaceutical and food industries in terms of value-added phytochemicals have increased rapidly in the last few years. Therefore, cost-effective and technically sound downstream processes have to be developed in order to supply standardized end-products. Depending on the utilization of the biomass or the culture broth, different types of facilities are needed for the recovery and quali-quantitative analysis. The aim of this chapter is to summarize mass transfer considerations and critically outline the developments in downstream processing of plant cell and tissue cultures by presenting fundamental knowledge as well as the advantages and disadvantages of some conventional and novel techniques such as supercritical fluid and membrane processes. Furthermore, state of the art for recovery and purification of secondary metabolites were discussed in the light of patents via Espacenet database covering US, Japan, European, Korean, and Chinese issued and applied patents and WIPO publications. Innovative downstream processes in combination with hyphenated techniques representing a modern approach to perform fast and reproducible analytical methods for quantification and quality assurance of secondary metabolites are major challenges for industrial-scale applications of plant cell and tissue cultures. © 2013 Springer-Verlag Berlin Heidelberg. All rights are reserved.Öğe Effects of natural oils and surfactants on cellulase production and activity(1989) Suha Sukan S.; Güray A.; Vardar-Sukan F.Emulsification of natural oils by a surfactant increases their efficiency as chemical antifoams. The presence of low concentrations of fatty acids or other surfactants have been reported to inhibit or stimulate microbial growth and/or product formation. The effects of different natural oils, Tween 80 and saponin on growth and cellulase production by T. reesei and S. pulverulentum have been investigated. It was found that in general, emulsification leads to higher cellulase activities in both cultures, though there are variations in enzyme levels depending on the presence or absence of Tween 80 and of different oils in growth media as well as the substrates used for cellulase assay. Copyright © 1989 Society of Chemical IndustryÖğe Effects of natural oils on foam collapse in bioprocesses(Kluwer Academic Publishers, 1991) Vardar-Sukan F.The foam collapse and foam formation properties of four different simulated fermentation media were compared in the presence and absence of natural oils. It was found that optimum effective natural oil concentration resulting in optimum foam suppression did not always correspond with the optimum for foam collapse, nor the optimum for maximum foam collapse rate. © 1991 Kluwer Academic Publishers.Öğe Efficiency of natural oils as antifoaming agents in bioprocesses(1988) Vardar-Sukan F.The effectiveness and efficiency of nine different natural oils were investigated using simulated fermentation media and several dimensionless coefficients were derived to provide a means for quantitative comparison. Furthermore, correlations between the physical and chemical properties of natural oils and of media and foam-suppression efficiencies of natural oils were sought. It was concluded that the effectiveness of a natural oil in foam suppression greatly varies with the type of medium. Copyright © 1988 Society of Chemical IndustryÖğe An Engineering approach to bioinformatics and its applications(Springer International Publishing, 2017) Yilmaz-Temel H.; Vardar-Sukan F.[No abstract available]Öğe Enzymatic hydrolysis of complex substrates following thermal pretreatment operations(Kluwer Academic Publishers, 1993) Vardar-Sukan F.; Sukan S.S.; Gaye O.-B.Most agroindustrial wastes generally undergo various thermal treatments during processing stages. The aim of this study was to determine the effect of different heat treatment methods on hydrolysis efficiency of such natural substrates. It was found that a wet thermal treatment generally increases the rate and degree of hydrolysis, while a dry one has a detrimental effect. © 1993 Chapman & Hall.Öğe Hazardous materials releases during the August 17, 1999 earthquake in Turkey(2004) Steinberg L.J.; Cruz A.M.; Vardar-Sukan F.; Ersoz Y.The Turkey earthquake of August 17, 1999 offers an unprecedented opportunity to study the potential for strong earthquakes to precipitate environmental catastrophes. In this study, the authors report on their field investigations in Turkey in which they document and assess how this earthquake of magnitude 7.4, centered in the industrial region of Turkey, led to hazardous materials releases to the air, water, and soil. They report on several case studies of industrial accidents which occurred as a result of the earthquake, including the Tupras refinery fire, the release of toxic acrylonitrile from a chemical plant, and the intentional release of gaseous ammonia from a fertilizer plant. Also documented and discussed are the emergency efforts directed towards responding to these incidents. Copyright ASCE 2004.Öğe In vitro release kinetics of pine bark extract enriched orange juice and the shelf stability(2010) Celiktas O.Y.; Isleten M.; Vardar-Sukan F.; Cetin E.O.Purpose: This paper seeks to demonstrate a functional beverage incorporating pine bark which is an unutilized forestry waste, determine in vitro release kinetics of enriched beverages, and antioxidant activities, besides assessing their shelf stabilities. Design/methodology/approach: Orange juice was enriched with Pinus brutia, Pinus pinea bark extracts, Pycnogenol ® . In vitro release kinetics was determined in pH 1.2 and pH 7.4. Ascorbic acid content, pH, titratable acidity, and colorimetric analyses were analyzed monthly for eight months to determine shelf life. Additionally, total phenol contents and radical scavenging activities were analyzed. Subsequently a consumer acceptance test was conducted among 200 participants. Findings: The release of all extracts in orange juices in pH 1.2 were slower than pH 7.4. The release results were fitted to Higuchi square root of time kinetic model with high determination coefficients. Although total titratable acidity values were in agreement with the trend of minor pH changes, prominent losses in antioxidant capacities, ascorbic acid contents and color were observed for the last two months suggesting a shelf life of six months. Female participants and young people had a greater tendency to consume such a beverage. Health concerns and flavor were the primary factors affecting their purchasing decisions. Research limitations/implications: Findings of the study demonstrated the effects of fortification with a plant-based extract as a substitute to the present practice of fortifying beverages with vitamins and minerals for a potential future market. Originality/value: The paper shows that juices fortified with pine bark extracts show higher antioxidant capacities and ascorbic acid contents compared to the control, thereby providing improved functionality. © Emerald Group Publishing Limited.Öğe Influence of supercritical carbon dioxide and methanolic extracts of rosemary on oxidation and sensory properties of wheat germ oil(2009) Yesil-Celiktas O.; Isleten M.; Karagul-Yuceer Y.; Bedir E.; Vardar-Sukan F.Both supercritical CO2 and methanolic extracts from the leaves of rosemary (Rosmarinus officinalis) harvested from three different locations of Turkey at four different times of the year were added at a concentration of 100 mg/kg to wheat germ oil. Wheat germ oil samples were stored in an incubator for 10 days at 50C in order to promote oxidation and for the efficacy of the extracts for stabilization purposes to be examined. Degree of oxidation was determined by peroxide and p-anisidine values, which were performed every 2 days. Extracts from Mersin and Canakkale regions performed better results. Additionally, June and September harvests had lower peroxide values. According to the descriptive sensory analysis, both locations and extraction methods were found to effect flavor. Some flavor attributes, such as wheatlike/starchy, fishy and rubbery/metallic changed during storage regardless of locations and extraction methods. Supercritical CO2 extracts performed better results in terms of both oxidation and sensory properties. © 2009 Wiley Periodicals, Inc.Öğe Mixing performance of air-lift fermenters against working volume and draft tube dimensions(Springer-Verlag, 1987) Sukan S.S.; Vardar-Sukan F.Mixing characteristics of a laboratory scale internal loop air-lift fermenter has been investigated. The effects of different draft tube dimensions and positions as well as varying levels of liquid height over the draft tube, on mixing time were determined. The results indicate the existance of an optimum liquid height and thus liquid volume with respect to mixing performance especially for the taller draft tubes. © 1987 Springer-Verlag.Öğe An optimization approach to scale up keratinase production byStreptomyces sp. 2M21 by utilizing chicken feather(Elsevier Ltd, 2015) Demir T.; Hameş E.E.; Öncel S.S.; Vardar-Sukan F.The aim of this study was to optimize the culture conditions for keratinase production by a new isolate, Streptomyces sp. 2M21 utilizing chicken feather as an alternative low-cost substrate. Contribution of different independent fermentation variables on keratinase activity was investigated by Plackett-Burman design. Parameters that have the highest contribution were selected for the optimization experiments which were carried out by using response surface methodology (RSM). Relative and mutual effects of fermentation variables on keratinase activity were analyzed with "23 Full Factorial Central Composite Design". Cultivation processes were implemented in 250ml Erlenmeyer flasks containing 50ml medium. Maximum keratinase activity was obtained under optimal conditions of 28°C, 5.0gl-1 chicken feather and 5.5 days of process time. As a result of the optimization studies, a 15 fold increase in keratinase activity was reached compared to the unoptimized conditions. Furthermore, similar results were obtained in the 2l bioreactor under optimized conditions. © 2015 Elsevier Ltd.Öğe Photo-bioproduction of hydrogen by Chlamydomonas reinhardtii using a semi-continuous process regime(2009) Oncel S.; Vardar-Sukan F.Photo-bioproduction of hydrogen by using green algae, Chlamydomonas reinhardtii, was investigated in batch and semi-continuous process regimes, in a continuous stirred type photobioreactor. Batch cultivation was carried out for 35 days which was one of the longest cited in literature. Total hydrogen production with batch culture reached 316 ml. The observations from the batch culture provided useful data about the production process. Three important observations were made from the batch cultivation. One was the requirement of a 2 day-lag time for the start of the hydrogen production. Second one was the fact that the maximum hydrogen production is reached at around day 4. Third one was the decline of hydrogen production after a week. Semi-continuous regime was preferred rather than a continuous one based on these data. Semi-continuous cultivation was continued for 127 days yielding a total hydrogen production of 1108 ml. In the semi-continuous process, the effects of parameters such as dilution ratio, dilution frequency and fresh medium addition were studied. The range of these parameters was also decided, based on the batch cultivation data. Each experiment testing for different parameters lasted for 7 days and thus five consecutive sets were completed in 35 days. The results showed a direct correlation between the amount and frequency of dilution and hydrogen production. Semi-continuous regime gave the opportunity of dividing the continuous production in consecutive batches and the process was in good relation with batch regime. © 2009 Professor T. Nejat Veziroglu.Öğe Plant bioinformatics: Decoding the phyta(Springer International Publishing, 2017) Hakeem K.R.; Malik A.; Ozturk M.; Vardar-Sukan F.This book: (i) introduces fundamental and applied bioinformatics research in the field of plant life sciences; (ii) enlightens the potential users towards the recent advances in the development and application of novel computational methods available for the analysis and integration of plant -omics data; (iii) highlights relevant databases, softwares, tools and web resources developed till date to make ease of access for researchers working to decipher plant responses towards stresses; and (iv) presents a critical cross-talks on the available high-throughput data in plant research. Therefore, in addition to being a reference for the professional researchers, it is also of great interest to students and their professors. Considering immense significance of plants for all lives on Earth, the major focus of research in plant biology has been to: (a) select plants that best fit the purposes of human, (b) develop crop plants superior in quality, quantity and farming practices when compared to natural (wild) plants, and (c) explore strategies to help plants to adapt biotic and abiotic/environmental stress factors. Accordingly the development of novel techniques and their applications have increased significantly in recent years. In particular, large amount of biological data have emerged from multi-omics approaches aimed at addressing numerous aspects of the plant systems under biotic or abiotic stresses. However, even though the field is evolving at a rapid pace, information on the cross-talks and/or critical digestion of research outcomes in the context of plant bioinformatics is scarce. "Plant Bioinformatics: Decoding the Phyta" is aimed to bridge this gap. © Springer International Publishing AG 2017. 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