Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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Article Citation - WoS: 12Citation - Scopus: 16Utilization of Orange Peel, a Food Industrial Waste, in the Production of Exo-Polygalacturonase by Pellet Forming Aspergillus Sojae(Springer Verlag, 2015) Büyükkileci, Ali Oğuz; Lahore, Marcelo Fernandez; Tarı, Canan; Büyükkileci, Ali Oğuz; 03.08. Department of Food Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyThe production of exo-polygalacturonase (exo-PG) from orange peel (OP), a food industrial waste, using Aspergillus sojae was studied in submerged culture. A simple, low-cost, industrially significant medium formulation, composed of only OP and (NH4)2SO4 (AS) was developed. At an inoculum size of 2.8 × 103 spores/mL, growth was in the form of pellets, which provided better mixing of the culture broth and higher exo-PG activity. These pellets were successfully used as an inoculum for bioreactors and 173.0 U/mL exo-PG was produced. Fed-batch cultivation further enhanced the exo-PG activity to 244.0 U/mL in 127.5 h. The final morphology in the form of pellets is significant to industrial fermentation easing the subsequent downstream processing. Furthermore, the low pH trend obtained during this fermentation serves an advantage to fungal fermentations prone to contamination problems. As a result, an economical exo-PG production process was defined utilizing a food industrial by-product and producing high amount of enzyme.Article 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.Article Citation - WoS: 14Citation - Scopus: 12Enhanced Production of Exo-Polygalacturonase From Agro-Based Products by Aspergillus Sojae(North Carolina University, 2011) Büyükkileci, Ali Oğuz; Tarı, Canan; Fernandez-Lahore, Marcello; Büyükkileci, Ali Oğuz; 03.08. Department of Food Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyAspergillus sojae has been previously shown to produce exo-polygalacturonase (exo-PG) in synthetic media, where the potential of the organism to utilize agricultural substrates was not considered so far. In this study, the utilization of agro-based products was taken into account in the enhanced production of exo-PG using an A. sojae mutant by applying statistical design methods. Complex sources (orange peel, wheat bran, and corn meal), simple sugar sources (glucose, maltrin, and sugar beet syrup), and two phosphate salts were screened using D-optimal design method. Orange peel yielded the highest exo-PG activity with all simple sugars and phosphate sources. According to the results of response surface methodology (RSM), the optimum concentrations of orange peel, sugar beet syrup, and (NH 4) 2SO 4 were found to be 10, 60, and 8 g L -1, respectively. The exo-PG activity under these conditions was 145.4 U m L -1 in shake flask cultures. In bioreactor studies enzyme production was induced at low pH values; thus highest production was obtained under uncontrolled pH conditions, in which the pH dropped to 2.0 in 72 h. As a result high exo-PG could be produced by an A. sojae mutant using a cost-effective medium containing agro-industrial substrates. Another important advantageous outcome was the low optimal pH, which is especially desired in industrial fermentations prone to contamination problems. In fact this highlights the easy adaptation of this fermentation to industrial scales.