Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection

Permanent URI for this collectionhttps://hdl.handle.net/11147/7148

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Author: search.filters.author.Buyukkileci, Ali OguzPublisher: search.filters.publisher.Elsevier

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  • Article
    Chain-Length Dependent and Synergistic Prebiotic Effects of Xylooligosaccharides and Xylan on the Fecal Microbiota of Mice in Vitro
    (Elsevier, 2025) Büyükkileci, Ali Oğuz; Güleç, Şükrü; Buyukkileci, Ali Oguz; 01. Izmir Institute of Technology; 03.08. Department of Food Engineering; 03. Faculty of Engineering
    Oligomeric and polymeric prebiotics differ in their structural complexity, which influences microbial accessibility and fermentation kinetics. This study investigated the microbial responses to xylooligosaccharides (XOS), xylan (XY), and their combinations in comparison with inulin (INU) using an in vitro model inoculated with BALB/c mice fecal microbiota. Temporal analyses over 48 h included substrate consumption, acid production, and changes in microbial diversity. XOS was rapidly fermented, yielding high acetate and lactate levels, whereas XY was utilized more slowly due to its polymeric structure. During XY fermentation, xylobiose (X2) and xylotriose (X3) accumulated transiently, suggesting a stepwise depolymerization and utilization mechanism. The XOS + XY mix showed enhanced prebiotic effect, producing the highest amount of acid (151.8 mmol/L) and notably promoted the simultaneous enrichment of Bifidobacterium (12.5-fold), Bacteroides (8.85-fold), and Lactobacillus (14.9-fold) species compared to individual treatments These findings demonstrate that coadministered XOS and XY highlights the potential for designing tailored prebiotic formulations to optimize microbiota modulation, with potential relevance for human health.
  • Article
    Citation - WoS: 3
    Citation - Scopus: 3
    An Ex Vivo Model for Evaluation of Prebiotic Activity of Xylan and Xylooligosaccharides
    (Elsevier, 2025) Güleç, Şükrü; Büyükkileci, Ali Oğuz; Buyukkileci, Ali Oguz; 03.08. Department of Food Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
    Ex vivo techniques can provide more physiologically significant insights into prebiotic activity and overcome some limitations of in vitro tests. In this study, an ex vivo model, formed of a large intestine of mice, was tested to assess the effects of the hydrocolloidal natural polymer, xylan (XY), and its hydrolysis product, xylooligosaccharides (XOS). XY and XOS were loaded separately into the cecum, proximal colon, and distal colon. Their utilization and short-chain fatty acid (SCFA) formation by the colonized microflora and levels of dominant phyla and key genera such as Bifidobacterium, Bacteroides, and Lactobacillus were followed. XY and XOS were metabolized in all sections, and SCFAs were released. The results suggest that the slower utilization of XY compared to XOS in the cecum can enable this polysaccharide to move towards distal parts of the large intestine and extend the sites of prebiotic activity. Unlike widely used in vitro models, the ex vivo model allowed testing the utilization pattern and effects of the prebiotics in the natural environment of the microflora and examining the intestinal sections separately.
  • Article
    Citation - WoS: 10
    Citation - Scopus: 11
    Enzymatic Hydrolysis of Organosolv-Pretreated Corncob and Succinic Acid Production by Actinobacillus Succinogenes
    (Elsevier, 2024) Büyükkileci, Ali Oğuz; Buyukkileci, Ali Oguz; 03.08. Department of Food Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
    In this study, the conversion of organosolv-treated corncob into monosaccharides through enzymatic sacchari-fication was investigated, with the resulting monosaccharides being utilized as a carbon source to produce succinic acid. The synergy between the cellulase and xylanase provided 76% cellulose and 64% xylan di-gestibility at 50 degrees C and pH 5.2. In separate hydrolysis and fermentation (SHF), Actinobacillus succinogenes pro-duced 12.7 g/L of succinic acid from the hydrolysate with 0.12 g/g yield based on the pretreated corncob. Simultaneous saccharification and fermentation (SSF) demonstrated better performance with 16 g/L succinic acid titer and 0.24 g/g yield, though SHF provided a higher production rate. The condition in the SSF (37 degrees C and pH near neutral) was suboptimal for the enzymes, thus the succinic acid production was limited by the saccharification step. These findings emphasize the potential of organosolv-treated corncob to serve as an enzymatic hydrolysis substrate without neutralization and detoxification, supplying glucose and xylose for succinic acid production by A. succinogenes.