Characterization of a novel endo-levanase from Azotobacter chroococcum DSM 2286 and its application for the production of prebiotic fructooligosaccharides
2021
Hövels, Marcel | Kosciow, Konrad | Deppenmeier, Uwe
Prebiotics are known for their ability to modulate the composition of the human microbiome and mediate health-promoting benefits. Endo-levanases, which hydrolyze levan into short-chain FOS, could be used for the production of levan-based prebiotics. The novel endo-levanase (LevB₂₂₈₆) from Azotobacter chroococcum DSM 2286, combines an exceptionally high specific activity with advantageous hydrolytic properties. Starting from levan isolated from Timothy grass, LevB₂₂₈₆ produced FOS ranging from DP 2 – 8. In contrast to endo-levanases described in the literature, LevB₂₂₈₆ formed minor amounts of fructose and levanbiose, even with greatly extended incubation. The combined activity of LevB₂₂₈₆ and the levansucrase LevS₁₄₁₇ from Gluconobacter japonicus LMG 1417 led to a one-step synthesis of levan-type FOS from sucrose. 387.4 ± 17.3 g L⁻¹ FOS were produced within 48 h by the production strategy based on crude cell extract of recombinant Escherichia coli expressing levS1417 and levB2286 simultaneously.
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