Sürdürülebilir Yeşil Kampüs Koleksiyonu / Sustainable Green Campus Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7755
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Article Citation - WoS: 33Citation - Scopus: 34Exploitation of Agricultural Wastes and By-Products for Production of Aureobasidium Pullulans Y-2311 Xylanase: Screening, Bioprocess Optimization and Scale Up(Springer Verlag, 2017) Yeğin, Sırma; Büyükkileci, Ali Oğuz; Sargın, Sayıt; Göksungur, Yekta; 03.08. Department of Food Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyThe potential of several agricultural wastes and by-products (wheat bran, oat bran, corn cob, brewer’s spent grain, malt sprout, artichoke stem, sugar beet pulp, olive seed, cotton stalk and hazelnut skin) was examined as the substrate for xylanase production by Aureobasidium pullulans Y-2311-1. Based on the screening studies, wheat bran was selected as the best substrate for further optimization studies. The effects of initial medium pH, temperature and incubation time on xylanase production in shake flask system were optimized by response surface methodology (RSM). The optimum levels of the process variables defined by the model (initial medium pH, 4.24; temperature, 30.27 °C; and incubation time 126.67 h) resulted in production of 85.19 U/ml xylanase. Taking the RSM optimized parameters in shake-flask scale into consideration; xylanase production was scaled up to bioreactor system with a working volume of 1.5 l. The peak of enzyme production was achieved after 126 h incubation that has previously been determined by RSM studies at shake flask level. Furthermore, the optimum levels of agitation and aeration in bioreactor system was found as 200 rpm and 1.5 vvm. Maximum enzyme production was close to 85 kU/l which could be translated into a productivity of 0.68 kU/l/h. No previous work considered the statistical optimization of xylanase production by A. pullulans on wheat bran and scale up of the bioprocess to a bioreactor systemArticle Citation - WoS: 13Citation - Scopus: 16Dilute-Acid Hydrolysis of Apple, Orange, Apricot and Peach Pomaces as Potential Candidates for Bioethanol Production(American Scientific Publishers, 2013) Üçüncü, Can; Tarı, Canan; Özen, Fatma Banu; Büyükkileci, Ali Oğuz; Özen, Banu; Büyükkileci, Ali Oğuz; Tarı, Canan; 03.08. Department of Food Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyChemical composition of four selected fruit pomaces (agro-industrial wastes) was evaluated. The effect of temperature, time, acid concentration and solid:liquid (S:L) ratio on dilute-acid hydrolysis of selected pomaces were investigated using 24 factorial and central composite design and optimum hydrolysis conditions were determined. A preliminary study was initiated using apple hydrolysate and the fungus Tricoderma harzianum in order to explore and demonstrate their potential uses in bioethanol production. Chemical composition of pomaces was promising as fermentation media. The highest reducing sugar yield from the optimization step was 31%, 49%, 56% and 52% for apple, apricot, orange and peach pomaces, respectively under optimum hydrolysis conditions. Neither furfural nor hydroxmethylfurfural (HMF) were detected in hydrolysates. The highest bioethanol production (1.67 g/L) was obtained in 6 days in a non-static incubator using Tricoderma harzianum pregrown in minimal medium. It was demonstrated that selected pomaces holds potential for bioethanol production and can be eliminated without being potential waste problem to the environment, with economical return. Although, this work is an initial study in showing the potential of these pomaces and T. harzianum in bioethanol production, an extensive study on the optimization of fermentation parameters is recommended for further increase of bioethanol production. Copyright © 2013 American Scientific Publishers All rights reserved.