Irem Deniz

Experimental design methods for bioengineering applications

Abstract Experimental design is a form of process analysis in which certain factors are selected to obtain the desired responses of interest. It may also be used for the determination of the effects of various independent factors on a dependent factor. The bioengineering discipline includes many different areas of scientific interest, and each study area is affected and governed by many different factors. Briefly analyzing the important factors and selecting an experimental design for optimization are very effective tools for the design of any bioprocess under question. This review summarizes experimental design methods that can be used to investigate various factors relating to bioengineering processes. The experimental methods generally used in bioengineering are as follows: full factorial design, fractional factorial design, Plackett–Burman design, Taguchi design, Box–Behnken design and central composite design. These design methods are briefly introduced, and then the application of these design methods to study different bioengineering processes is analyzed.

Trends in red biotechnology: Microalgae for pharmaceutical applications

Abstract This chapter introduces the pharmaceutical applications of microalgae with respect to their potential properties. It overviews the previous and recent studies on antioxidant, antiinflammatory, antitumor, anticancer, antimicrobial, antiviral and antiallergic activities of microalgal bioactive molecules. It explains the potential mechanism underlying the effects of these molecules with the related pathways. By the end of the chapter the future prospects on the red biotechnology, including the developments in research and industry are explained. A full discussion of recent examples is included to raise the possibility of microalgal resources to become a promising compound in various types of industrial areas with the key concept of potential usage.

Evaluation of scale-up parameters of bioethanol production from Escherichia coli KO11 / [Escherichia coli KO11 suşundan biyoetanol üretimi için ölçek büyütme parametrelerinin değerlendirilmesi]

Abstract Objective: In recent years, increased attention has been devoted to the conversion of biomass into fuel ethanol, as one of the cleanest liquid fuel alternatives to fossil fuels. However, industrial production of bioethanol is related with successful scaling-up studies. Methods: In this study, the experimental designs of scale-up procedures based on constant mixing time, impeller tip speed and oxygen mass transfer coefficient were performed in 8 L stirred tank reactor and were compared in terms of product yield and productivity with those obtained from 2 L stirred tank reactor using quince pomace as a substrate for bioethanol production by Escherichia coli KO11. Results: Scale-up based on constant mixing time yielded a maximum ethanol concentration of 23.42 g/L which corresponded to 0.4 g ethanol/ g reduced sugar in 8 L stirred tank reactor. Moreover, shear stress increased only 1.1 fold which resulted in low cell damage and high cell viability. Conclusion: Constant mixing time was identified as the most important key parameter especially for scaling-up of viscous fermentation broths of bioethanol production due to the significance of the homogeneity. Özet Amaç: Son yıllarda fosil yakıtlara alternatiflerden biri olarak biyokütlenin dönüşümüyle etanol eldesi çok önem kazanmıştır. Endüstriyel ölçekte biyoetanol üretimi, başarılı bir ölçek büyütmeye bağlıdır. Metod: Bu çalışmada, 8 L karıştırmalı tank reaktörde sabit karışma süresi, sabit bıçak ucu hızı ve sabit oksijen kütle transfer katsayısına göre ölçek büyütme prosedürleri gerçekleştirilmiştir. Sonuçlar, Escherichia coli KO11 suşundan ayva posası ile 2 L reaktörde elde edilen sonuçlarla ürün verimi ve verimliliği bakımından karşılaştırılmıştır. Bulgular: 8 L karıştırmalı tank reaktörde maksimum etanol konsantrasyonu (23.42 g/L), 0.4 g etanol/g indirgen şeker verimiyle sabit karışma süresine göre yapılan ölçek büyütmede elde edilmiştir. Ayrıca, kayma gerilimi sadece 1.1 kat artmıştır ve bu durum düşük hücre hasarı ve yüksek hücre canlılığıyla sonuçlanmıştır. Sonuç: Sabit karışma süresi, biyoetanol üretiminde homojenitenin önemi açısından özellikle viskoz fermentasyon sıvıları için en önemli parameter olarak tanımlanmıştır.

Optimization of physical parameters for phycobiliprotein extracted from Oscillatoria agardhii and Synechococcus nidulans / Oscillatoria agardhii ve Synechococcus nidulans türlerinden fikobiliprotein ekstraksiyonu için fiziksel parametrelerin optimizasyonu

Abstract Objective: Physical process parameters play a major role in the cultivation of cyanobacteria to provide high yield. The aim of this study was to optimize physical parameters such as light intensity and agitation rate which might affect the phycobiliprotein formations for cyanobacterial strains of Oscillatoria agardhii and Synechococcus nidulans using response surface methodology. Methods: The cyanobacterial strains were cultured in 250 mL flasks containing 100 mL of EM medium in orbital shaking incubator under the temperature of 22±2°C at different light intensities and agitation rates for 10 days. The experimental design was carried out using 22 full-factorial experiments design with four axial points (α=1.414) and five replicates at the central point (65 μmol photons m-2s-1 and 150 rpm), according to the central composite design. Results: The optimization solution of O. agardhii (approximately at 156 rpm under the light intensity of 65 μmol photons m-2s-1) was selected because it resulted in the highest predicted response with the highest desirability. Furthermore, the optimization solution for S. nidulans suggested the phycobiliprotein amount of 9.95 mg/L obtaining at the agitation rate of 185 rpm under the light intensity of 46 μmol photons m-2s-1. The optimized results were reliable and the regions studied were proven to be statistically adequate. Conclusion: High agitation rate stimulated the faster growth than increased the light intensity for the growths of cyanobacterial strains. Ozet Amac: Siyanobakteri kultivasyonunda yuksek verime ulaşmak icin fiziksel proses parametreleri ana rolu oynamaktadır. Bu calışmada amac, yanıt yuzey metodu ile Oscillatoria agardhii ve Synechococcus nidulans turlerinin fikobiliprotein oluşumunu etkileyen ışık şiddeti ve calkalama hızı gibi fiziksel proses parametrelerini optimize etmektir. Metod: Siyanobakteri turleri 250 ml’lik erlenlerde 100 mL EM ortamında 22±2°C sıcaklığında farklı ışık şiddetleri ve karıştırma hızlarında 10 gunluk periyotlarda kultive edilmiştir. Deney tasarımı, 22 faktoriyel kullanılarak CCD ile gercekleştirilmiştir. Bulgular: O. agardhii icin en yuksek tahmini cevap ile uretimin 156 rpm’de 65 μmol photons m-2s-1 ışık şiddetinde olması gerektiği belirlenmiştir. Diğer taraftan, S. nidulans optimizasyon cozumu 9.95mg/L fikobiliprotein miktarına ulaşmak icin uretimin 185 rpm’de 46 μmol fotons m-2s-1 ışık şiddetinde gercekleştirilebileceğini gostermiştir. Sonuc: Yuksek calkalama hızı, yuksek ışık şiddetine kıyasla siyanobakteri turlerinin daha hızlı uremesini tetiklemiştir.