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- MakaleAçık Erişim2025Scopus SJRQ2Liquorilactobacillus hordei SK6 and Liquorilactobacillus mali SK26 from Traditional Water Kefir Produce Dextrans with Technological Roles
Edis, Kader Korkmaz; İspirli, Hümeyra; Yilmaz, Mustafa Tahsin; Dertli, Enes
The significance of exopolysaccharides (EPS) in various applications has garnered increasing attention. In this study, two bacteria, Liquorilactobacillus hordei SK6 and Liquorilactobacillus mali SK26, isolated from traditional water kefir grains, produced 8.89 g/L and 7.2 g/L of homopolymeric glucan, respectively. NMR analysis revealed that both glucans were dextrans composed of (1 → 6)-linked α-d-glucose units, with (1 → 3)-linked α-d-glucose units serving as branching points, accounting for 5.3 ± 0.2% in dextran SK6 and 2.7 ± 0.15% in SK26. FTIR and XRD analyses further confirmed the amorphous nature of the dextrans, although dextran SK6 exhibited micro-arranged structures. Thermal characterization using TGA and DSC showed degradation temperatures of 298.5 °C for dextran SK6 and 282.1 °C for dextran SK26. Clear differences in morphological properties were observed using AFM and SEM. These findings provide valuable insights into dextran-producing strains and their potential applications in various industries.
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İncele - MakaleYalnız künye2020Scopus SJRQ1Impact of glucan type exopolysaccharide (EPS) production on technological characteristics of sourdough bread
İspirli, Hümeyra; Özmen, D.; Yılmaz, Mustafa Tahsin; Sağdıç, O.; Dertli, Enes
In this study, technological role of α-glucan with (α1-3) and (α1-6) glycosidic linkages produced by Lactobacillus reuteri E81 on sourdough rheology and bread texture was investigated. To achieve this, a glucan deficient ΔgtfA mutant was produced by the deletion of the glucansucrase gene from strain E81. By comparison of glucan-positive and glucan-negative strains for rheological properties of sourdough revealed that in situ α-glucan production resulted in higher elasticity in sourdough. However, no additional effect of in situ glucan on textural characteristics of bread was observed although addition of glucan ex situ at 0.09% level significantly decreased bread hardness. Scanning Electron Microscopy (SEM) images of lyophilized sourdoughs confirmed association of glucan and starch granules forming a film like structure in sourdough.
AtıfScopus71WoS58OpenAlex67İncele - MakaleAçık Erişim2019Scopus SJRQ2Physicochemical characterisation of an α-glucan from Lactobacillus reuteri E81 as a potential exopolysaccharide suitable for food applications
İspirli, Hümeyra; Sagdic, Osman; Yılmaz, Mustafa Tahsin; Dertli, Enes
Lactobacillus reuteri strain (E81) is an alpha glucan producer from traditional sourdough and the physicochemical characteristics of this glucan was determined in this study. The HPLC analysis confirmed the presence of glucose as the only sugar monomer in the repeating structure of this exopolysaccharide (EPS). The functional groups within the glucan structure was detected by FTIR analysis. The scanning electron microscopy (SEM) analysis demonstrated the web-like branched structure of the glucan. Morphological characterisation of the glucan E81 by atomic force microscopy (AFM) analysis showed clear roundness lumps and chains. Importantly, thermal characteristics of glucan E81 determined by thermogram analysis (TGA) and differential scanning calorimeter (DSC) analysis revealed that glucan E81 has a melting point of 290 °C making it promising to be used in thermal processed foods including sourdough bread.
AtıfScopus77WoS71OpenAlex77İncele - MakaleAçık Erişim2019Scopus SJRQ3Characterization of a glucansucrase from Lactobacillus reuteri E81 and production of malto-oligosaccharides
İspirli, Hümeyra; Yüzer, Mustafa Onur; Skory, Christopher; Colquhoun, Ian J.; Sağdıç, Osman; Dertli, Enes
Glucansucrases, which can be produced by different Lactic Acid Bacteria (LAB), catalyze the synthesis of α-glucans with different structures and properties using sucrose as substrate. In this study, a novel glucansucrase (GTFA) from Lactobacillus reuteri E81 was identified and heterologously expressed. Alignments of GTFA with other glucansucrases revealed its novelty and a putative 3D model structure was obtained. The biochemical properties of the truncated enzyme without the N-terminal variable region, GTFA-ΔN, was characterized. The Km and Vmax were found to be 7.5 mM and 1.49 IU/mg, respectively, and it showed optimum activities at pH 7 and at 50 °C. The GTFA-ΔN produced in vitro an α-glucan with (α1 → 3) and (α1 → 6) glycosidic linkages using sucrose as the substrate. Importantly, GTFA-ΔN synthesized DP = 9 oligosaccharides using sucrose and maltose as the donor and acceptor sugars, respectively, as detected by TLC, HPLC, LC-MS and NMR analysis.
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