Characterization of levan produced by a Paenibacillus sp. isolated from Brazilian crude oil


A levan-type fructooligosaccharide was produced by a Paenibacillus strain isolated from Brazilian crude oil, the purity of which was 98.5% after precipitation with ethanol and dialysis. Characterization by FTIR, NMR spectroscopy, GC-FID and ESI-MS revealed that it is a mixture of linear beta(2 -+ 6) fructosyl polymers with average degree of polymerization (DP) of 18 and branching ratio of 20. Morphological structure and physicochemical properties were investigated to assess levan microstructure, degradation temperature and thermomechanical features. Thermal Gravimetric Analysis highlighted degradation temperature of 218 degrees C, Differential Scanning Calorimetry (DSC) glass transition at 81.47 degrees C, and Dynamic Mechanical Analysis three frequency-dependent transition peaks. These peaks, corresponding to a first thermomechanical transition event at 86.60 degrees C related to the DSC endothermic event, a second at 170.9 degrees C and a third at 185.2 degrees C, were attributed to different glass transition temperatures of oligo and polyfructans with different DP. Levan showed high morphological versatility and technological potential for the food, nutraceutical, and pharmaceutical industries.



subject category

Biochemistry & Molecular Biology; Chemistry, Applied; Polymer Science


Mendonca, CMN; Oliveira, RC; Freire, RKB; Piazentin, ACM; Pereira, WA; Gudina, EJ; Evtuguin, DV; Converti, A; Santos, JHPM; Nunes, C; Rodrigues, LR; Oliveira, RPS

our authors


The authors are grateful to the financial support by Sao Paulo Research Foundation (FAPESP) within Grants 2020/13271-6 and 2018/25511-1. Additionally, the authors acknowledge the financial support by National Council for Scientific and Technological Development CNPq and by Coordination for the Improvement of Higher Education Personnel (CAPES), Finance Code 001. In addition, this study was supported by the Portuguese Science Foundation (FCT) under the scope of the strategic funding of UID/BIO/04469/2020 unit and the Project FOSYNBIO (POCI-01-0145-FEDER-029549).

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