Expanding the high-pH range of the sucrose synthase reaction by enzyme immobilization

• DOI: 10.1016/j.jbiotec.2024.11.005
• Publication Date: 2024-11-08T21:43:59Z
• Authors: Hui Liu; Annika J.E. Borg; Bernd Nidetzky

The glycosylation of an alcohol group from a sugar nucleotide substrate involves proton release, so the reaction is favored thermodynamically at high pH. Here, we explored expansion alkaline pH range sucrose synthase (SuSy; EC 2.4.1.13) to facilitate enzymatic uridine 5'-diphosphate (UDP)-glucose. apparent equilibrium constant SuSy (UDP-glucose + fructose ↔ UDP) 30 °C increases by ∼4 orders magnitude as raised 5.5 9.0. However, in solution loses ≥80 % its maximum productivity ∼7 when conditions (pH 9.0) are used. We therefore immobilized on nanocellulose-based biocomposite carriers (∼48 U/g carrier; ≥ 50 effectiveness) and reveal carrier-bound enzyme substantial broadening pH-productivity profile pH, with up 80 capacity retained 9.5. Using automated control ∼9.0, demonstrate near-complete conversion (≥ 96 %) UDP-glucose (each 100 mM) into sucrose, expected (K