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Polysaccharides are present in all life forms and display multifarious biochemical structures. They are important natural products, present in microorganisms, animals and plants and exhibit various biological functions. Microbial exopolysaccharides (EPSs) are synthesized by both eukaryotes and prokaryotes and they mostly provide cell adhesion and protection against negative environmental conditions. In comparison to other natural sources, microbial EPSs usually have considerably shorter production times and their extraction is quite simple. These polysaccharides present a wide variety of structures and physicochemical properties, allowing the possibility to apply them in areas ranging from use as rheology modifiers of food systems to therapeutic agents. Microbial EPSs have various applications in cosmetic, food, and textile industries and they have been used widely in diverse fields of the food industry to enhance the quality of the product. Moreover, they have an important role in health through antimicrobial, antioxidant, anticancer, and cholesterol-lowering effects, antiviral activities and prebiotic properties. This review focuses on bioactive characteristics, applications and resources of exopolysaccharides produced by microorganisms.

Ağır metallerin çoğu hayatsal fonksiyonlar için gereksiz olup belirli bir konsantrasyonda insan vücuduna zarar verebilir. Çevre kirliliği nedeniyle; göl, okyanus ve toprakta artış gösteren ağır metaller insanlık için ciddi riskler getirmektedir. Bu nedenle, çevresel örneklerin ağır metal içeriğinin belirlenmesi için yeni ve hassas yöntemler geliştirmek gerekli ve önemlidir.Bu çalışmada, Yüksek Çözünürlüklü Sürekli Işın Kaynaklı Alevli Atomik Absorpsiyon Spektrometresi (HR CS- FAAS) kullanılarak meyve suları ve termomineral sularda eser miktarda kurşun, bakır ve nikel miktarının belirlenmesi için yeni bir katı faz ekstraksiyon (SPE) yöntemi geliştirilmiştir. Çalışmada, asma dalından (ACVS) elde edilen bir aktif karbon, adsorban olarak kullanılmıştır. Kolon tekniği ayırma ve zenginleştirme işleminde uygulanmıştır. En uygun koşulları belirlemek için; örnek çözeltinin pH'ı, geri kazanım çözeltisinin türü ve konsantrasyonu, örnek çözeltinin ve geri kazanım çözeltisinin akış hızı, örnek çözeltinin hacmi ve yabancı iyonların analit iyonlarının geri kazanım verimine etkisi incelendi.ACVS içeren kolonda, kurşun, bakır ve nikel için tespit sınırları (LOD) 0,36, 0,69 ve 0,28 µg L-1, zenginleştirme faktörü 60 olarak belirlendi. Yöntemin doğruluğu bilinen miktarda analit iyonlarının gerçek örneklere ilave edilmesiyle yapılan geri kazanma çalışmalarıyla kontrol edildi. Geliştirilen metot, çeşitli meyve sularına ve termomineral su örneklerine başarıyla uygulandı.Aralık 2019 – xiii+ 55 SayfaAnahtar Kelimeler: Meyve Suyu, Termomineral Sular, Aktif Karbon, Alevli Atomik Absorpsiyon Spektrometri, Ağır metaller Most heavy metals are unnecessary for life functions and all heavy metals above a given concentration can damage the human body. Due to environmental pollution, heavy metals entering increasing amounts of lakes, oceans and soil bring serious risks to humanity. Therefore, it is necessary and important to develop new and sensitive methods for the determination of the heavy metal content of environmental, biological and food samples.In the present study, a new solid phase extraction (SPE) method was developed for the determination of trace amount of lead, copper and nickel in fruit juices and thermomineral waters by using High-Resolution Continuum Source Flame Atomic Absorption Spectrometry (HR CS- FAAS ). In the study, an activated carbon obtained from the vine shoots (ACVS) was used as adsorbents. The column technique has been applied in the seperation and enrichment process. In order to determine the most favorable conditions; the pH of the sample solution, the type and concentration of the recovery solution, the flow rate of the sample solution and the recovery solution, the volume of the sample solution, the effect of foreign ions on the yield of recovery of analyte ions was investigated.In the column containing ACVS, for the lead, copper and nickel the detection limits (LOD) 0.36, 0.69 and 0.28 µg L-1, the enrichment factor 60. The accuracy of the method was checked by recovering of the known amount analyte ions added to the actual sample. The developed method has been successfully applied to a variety of fruit juices and thermomineral water samples.December 2019- xiii+ 55 PagesKeywords: Fruit Juice, Thermoimineral Waters, Activated Carbon, Flame Atomic Absorption Spectrometry, Heavy metals 68

pastoris. In this study four secretion signal sequences were evaluated for extracellular production of Aspergillus niger xylanase (XylB) in Pichia pastoris. These sequences were namely; Saccharomyces cerevisiae ?-mating factor (?-MF), Human Serum Albumin (HSA), P. pastoris Acid Phosphatase (PHO1) and P. pastoris Protein with Internal Repeats (PIR1) secretion signals. The codon optimized XylB gene fused to secretion sequences was expressed under the AOX1 promoter of P. pastoris in KM71H strain. Xylanase enzyme activities for single-copy clones with ?-MF, HSA, PHO1 and PIR1 as secretion sequence were 170, 123, 139 and 250. U/mL, respectively, after 48. h induction period. P. pastoris PIR1 leader sequence resulted highest xylanase enzyme activity at shake-flask scale among the tested secretion signal sequences. The xylanase was purified with a single step Ni-NTA purification method. The optimum temperature and pH for recombinant xylanase was 40-50. °C and pH 5, respectively. Additionally, xylanase activity in purified enzyme was stable over a wide pH range (pH 3-7) and temperature of up to 50. °C. Specific activity of purified xylanase was 13,271. U/mg. © 2014 Elsevier B.V., Firat University Scientific Research Projects Management Unit: 2013.02.0121.018, This project was supported by Akdeniz University Scientific Research Projects Coordination Unit with project number 2013.02.0121.018.