Carboxyalkylated cullulose nanocrystals for novel applications

Cellulose nanocrystals (CNC), rigid rod-like nanoparticles, are derived from cellulose through acid hydrolysis and are considered as emerging nanomaterials according to their beneficial properties and commercial availability. In this thesis, the use of CNC derivatives in novel applications was explored. To make CNC more suitable for these applications, carboxyalkylation has been carried out to increase the charge density of CNC and induce hairy structure on the surface of CNC. Since the dispersibility of kaolinite particles are very crucial in their end-use applications ranging from cosmetics to drilling, carboxymethylated CNC was used as a dispersant to increase the stability of such suspensions. In the meantime, CNC was produced in different sizes prior to carboxymethylation to analyze the effect of CNC size on its performance as a dispersant. It was observed that the larger the modified CNC, the higher the charge density, and thus, the more the CNC adsorption to kaolinite particles. Hence, with increasing the CNC size, a lower dosage of modified CNC was observed to be required for attaining better kaolinite stability, which would be industrially attractive. Another fundamental discovery of this research study was that the functional groups on the carboxymethylation of CNC was observed to play a more critical role in the settling affinity of the kaolinite particles than the CNC size

Seyhan nehri kıyısından izole edilen bacillus sp.’den lasparajinaz izolasyonu ve karakterizasyonu.

TEZ11646Tez (Yüksek Lisans) -- Çukurova Üniversitesi, Adana, 2016.Kaynakça (s. 63-71) var.x, 73 s. : res. (bzs. rnk.), tablo ; 29 cm.L-asparajinaz terapötik özelliğiyle, tümör hücrelerinin özellikle akut lenfoblastik lösemi tedavilerinde kullanılabilir bir anti-tümör ajan olarak büyük ilgi çekmektedir. Ayrıca, L-asparajinaz nişastalı gıdalarda kanserojen olan akrilamitin gıda işleme yardımcısı olarak, seviyesini önemli ölçüde azaltabilmektedir. Bu çalışmada, Adana'da Seyhan nehri kıyısından alınmış toprak örneğinden 40 adet Bacillus suşu izole edilmiştir. Suşların L-asparajinaz üretim yeteneklerini saptamak amacıyla L-asparajin içeren modifiye M9 besiyeri kullanılmıştır. Enzim üretme yeteneğinde olan 4 suş saptanmış, bunlardan Z12 nolu suş hem kalitatif hem de kantitatif deneylerde en yüksek aktivite göstermiştir. Z12 nolu suş mikroskobik (Gram +, endospor + basil) ve biyokimyasal testler (VITEK-2, % 88) ile Bacillus olarak tanımlanmıştır. Optimum enzim üretimi; 0.75% L-asparajin ihtiva eden besiyerinde (pH 7.0) 5 gün ve 40°C’de gerçekleştirilmiştir. L-asparajinaz geniş pH ve sıcaklık aralığında aktivite göstermesine rağmen optimum aktivite pH 8.0 ve 40oC’de gözlenmiştir. Enzim farklı tamponlar (pH 7.0- 12.0) ile 60 dk muamele edildiğinde pH 7.0’de aktivitenin %100 korunduğu gözlenmiştir. Değişen sıcaklılarda (40-100oC) 60 dk ön inkübasyondan sonra enzim 50oC’de aktivitesini %100 korumasına rağmen, 70oC’nin üzerindeki sıcaklıklarda aktivitesinin %50'sini kaybetmiştir. Üre ve EDTA enzim aktivitesini yaklaşık 50%’e kadar azaltmış, ancak, MgCl2 enzim aktivitesini %20 düzeyinde arttırmıştır. Zymogram ve SDS-PAGE analiziyle enzimin 128 kDa boyutunda tek bant olduğu gözlenmiştir. Sonuçlara göre, doğal bir izolat olan Bacillus Z12 suşu L-asparajinaz üreticisi olarak endüstriyel amaçlı kullanılabilir.The therapeutic enzyme L-asparaginase has received great attention as an antitumor agent for its treatment of tumor cells, particularly in acute lymphoblastic leukemia. In addition, as a food processing aid, L-asparaginases can significantly reduce the level of the carcinogen acrylamide in starchy foods. In this study, 40 Bacillus strains were isolated from the soil of the Seyhan riverside in Adana. Modified M9 medium containing L-asparagine as a substrate was used in order to evaluate the strain’s L-asparaginase producing potential. 4 strains were determined as enzyme producing strains and among them, isolate No. Z12 showed the greatest activity in both qualitative and quantitative experiments. Isolate No. Z12 was identified as Bacillus sp. by microscopic (Gram +, endospore +, bacil) and biochemical tests (VITEK-2, 88%). The optimal enzyme production was carried out in a medium containing 0.75% L-asparagine as a substrate (pH 7.0) at 40°C for 5 days. Although L-asparaginase showed the activity over a wide range of pH values and temperature, optimum activity was observed at pH 8.0 at 40oC. When the enzyme was treated with different buffers (pH 7.0-12.0) for 60 min, it was observed that the activity was 100% preserved at pH 7.0. After pre-incubating the enzyme at different temperatures (40oC-100oC) for 60 min, the enzyme was 100% stable at 50oC, whereas the enzyme lost 50% of its activity in temperatures over 70oC. Urea and EDTA decreased the enzyme activity up to approximately 50%, however, MgCl2 increased the enzyme activity up to 20%. Using Zymogram and SDS-PAGE analyses, a single band was observed for the enzyme with the molecular weight of 128 kDa. According to the results, the native Bacillus Z12 strain can be used as a producer of L-asparaginase with industrial purposes.Bu çalışma Ç.Ü. Bilimsel Araştırma Projeleri Birimi tarafından desteklenmiştir. Proje No: FYL-2015-3928

Production and characterization of L-asparaginase from native Bacillus sp.

European Biotechnology Congress -- MAY 25-27, 2017 -- Dubrovnik, CROATIAWOS: 000413585400199

Production of Flocculants, Adsorbents, and Dispersants from Lignin

Currently, lignin is mainly produced in pulping processes, but it is considered as an under-utilized chemical since it is being mainly used as a fuel source. Lignin contains many hydroxyl groups that can participate in chemical reactions to produce value-added products. Flocculants, adsorbents, and dispersants have a wide range of applications in industry, but they are mainly oil-based chemicals and expensive. This paper reviews the pathways to produce water soluble lignin-based flocculants, adsorbents, and dispersants. It provides information on the recent progress in the possible use of these lignin-based flocculants, adsorbents, and dispersants. It also critically discusses the advantages and disadvantages of various approaches to produce such products. The challenges present in the production of lignin-based flocculants, adsorbents, and dispersants and possible scenarios to overcome these challenges for commercial use of these products in industry are discussed