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- MakaleYalnız künye2026Scopus SJRQ1Structural and physicochemical characterisation of branched dextrans produced by an active α-(1→2) branching sucrase from Apilactobacillus kunkeei PDER37
İspirli, Hümeyra; Dertli, Enes
Recently, branching sucrases encoded in the genomes of certain Lactic Acid Bacteria (LAB) strains have become novel enzymes to obtain branched α-glucans. In this study an active α-(1 → 2) branching sucrase from Apilactobacillus kunkeei PDER37 was expressed, characterised and distinct branched dextrans was obtained with reactions under different sucrose: dextran ratio. Structural characterisation by 1H and 13C NMR analysis demonstrated the branching of the dextran with (1 → 2)-linked α- d -glucose units with no alteration in the final structure depending on sucrose: dextran ratio (D0) but this ratio was effective for the determination of the molecular weights of the branched dextrans (D1, D2 and D3). FTIR analysis further supported the dextran structures and suggested the higher accumulation of the α-Glc units in the branched dextrans. Thermal characterisation of the branched dextrans obtained by TGA and DSC analysis suggested the increased hygroscopicity of the branching units. Both SEM and AFM analysis demonstrated more porous chain like structures in the branched dextrans. This study provides valuable information on the role of active α-(1 → 2) branching sucrase (BS37) for the production of branched dextrans with potential increased physicochemical status applicable for food and other industries.
- MakaleAçık Erişim2023Scopus SJRQ2Characterisation of dextran AP-27 produced by bee pollen isolate Lactobacillus kunkeei AP-27
Yilmaz, Mustafa T.; İspirli, Hümeyra; Alidrisi, Hassan; Taylan, Osman; Dertli, Enes
An exopolysaccharide (EPS) produced by bee pollen isolate Lactobacillus kunkeei AP-27 was characterised in this study. EPS monomeric composition of strain AP-27 was characterised by High-performance liquid chromatography (HPLC) analysis and glucose was the only sugar in the EPS repeating unit. Structural analysis of glucan AP27 by 1H and 13C Nuclear magnetic resonance (NMR) analysis demonstrated that this glucan was a dextran ((1→6)-linked α-D-glucose units as the main body) consisting very low level of (1 → 4)-linked α-D-glucose units (∼ 0.5 %). Dextran AP-27 had a degradation temperature of 308 °C that revealed its superior thermal strength identified by Thermogravimetric (TGA) and Differential scanning calorimetry (DSC) analysis. The molecular weight of dextran AP-27 was determined to be 25 kDa by Gel Permeation Chromatography (GPC) analysis. Crystallographic properties of dextran AP-27 was determined by X-ray diffraction (XRD) analysis that divulged its amorphous feature. Scanning Electron Microscopy (SEM) analysis was applied for microstructural characterisation of dextran AP-27 which revealed its regular sphere like characteristics. These findings suggest that Lactic Acid Bacteria (LAB) strains from different environments such as bee products can be the source for distinct EPS producer strains.
AtıfScopus9WoS8OpenAlex7
İncele - MakaleYalnız künye2022Scopus SJRQ1Characterisation and functional roles of a highly branched dextran produced by a bee pollen isolate Leuconostoc mesenteroides BI-20
Yilmaz, Mustafa Tahsin; İspirli, Hümeyra; Taylan, Osman; Taşdemir, Volkan; Sagdic, Osman; Dertli, Enes
Lactic Acid Bacteria (LAB) from different niches can be responsible for the production of distinct exopolysaccharides (EPS) that might possess important structural and technological features. In this respect, the aim of this study was to isolate an EPS producer LAB strain from bee pollen environment. Leuconostoc mesenteroides BI-20 with a slimy-mucoid colony morphology was identified from bee pollen and the structural, technological and functional characteristics of EPS produced by this strain were determined. EPS BI-20 was a highly branched dextran containing 20% (1 → 3)-linked α-D-glucose branches determined by 1H and 13C NMR analysis. The presence of (1 → 6)/(1 → 3)-linked α-D-glucose linkages in dextran BI-20 was also confirmed by FTIR analysis. Dextran BI-20, with a molecular weight of 1 × 108 Da, possessed strong thermal properties, amorphous nature and highly branched and fibrous microstructural characteristics determined by DSC, TGA, XRD and SEM analysis, respectively. In terms of functional roles, dextran BI-20 demonstrated strong antioxidant capacity detected by ABTS and CUPRAC tests. Finally, no digestion was observed in dextran BI-20 under simulated gastric conditions. Results of this study unveiled techno-functional characteristics of dextran BI-20 produced by a bee pollen isolate LAB strain.
AtıfScopus39WoS36OpenAlex39İncele - MakaleYalnız künye2022Scopus SJRQ1Structural and bioactive characteristics of a dextran produced by Lactobacillus kunkeei AK1
Yilmaz, Mustafa Tahsin; İspirli, Hümeyra; Taylan, Osman; Bilgrami, Anwar L.; Dertli, Enes
In this study, structural and techno-functional characteristics of an exopolysaccharide (EPS) produced by Lactobacillus kunkeei AK1 were determined. High-performance liquid chromatography (HPLC) analysis demonstrated that EPS AK1 was composed of only glucose units. 1H and 13C Nuclear magnetic resonance (NMR) analysis revealed that EPS AK1 was a dextran type EPS containing 4.78% (1 → 4)-linked α-D-glucose branches. The molecular weight of EPS AK1 was determined to be 45 kDa by Gel Permeation Chromatography (GPC) analysis. A high level of thermal stability up to 280 °C was determined for dextran AK1 detected by Differential scanning calorimetry (DSC) and Thermogravimetric analysis (TGA). Dextran AK1 appeared as regular spheres with compact morphology and as irregular particles in the solution with no clear cross-linking between the chains of the polysaccharide observed by Scanning electron microscopy (SEM) and Atomic force microscopy (AFM) analysis, respectively. X-ray diffraction analysis (XRD) analysis demonstrated that dextran AK1 had a crystalline structure. A relatively strong antioxidant activity was observed for dextran AK1 determined by 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2′-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) radical scavenging and cupric reducing antioxidant capacity (CUPRAC) tests. Finally, only a digestion ratio of 3.1% was observed for dextran AK1 following the in vitro simulated gastric digestion test.
AtıfScopus43WoS39OpenAlex41
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