Abstract
Sialo-oligosaccharides are important products of emerging biotechnology for complex carbohydrates as nutritional ingredients. Cascade bio-catalysis is central to the development of sialo-oligosaccharide production systems, based on isolated enzymes or whole cells. Multienzyme transformations have been established for sialo-oligosaccharide synthesis from expedient substrates, but systematic engineering analysis for the optimization of such transformations is lacking. Here, we show a mathematical modeling-guided approach to 3ʹ-sialyllactose (3SL) synthesis from N-acetyl- d-neuraminic acid (Neu5Ac) and lactose in the presence of cytidine 5ʹ-triphosphate, via the reactions of cytidine 5ʹ-monophosphate-Neu5Ac synthetase and α2,3-sialyltransferase. The Neu5Ac was synthesized in situ from N-acetyl- d-mannosamine using the reversible reaction with pyruvate by Neu5Ac lyase or the effectively irreversible reaction with phosphoenolpyruvate by Neu5Ac synthase. We show through comprehensive time-course study by experiment and modeling that, due to kinetic rather than thermodynamic advantages of the synthase reaction, the 3SL yield was increased (up to 75%; 10.4 g/L) and the initial productivity doubled (15 g/L/h), compared with synthesis based on the lyase reaction. We further show model-based optimization to minimize the total loading of protein (saving: up to 43%) while maintaining a suitable ratio of the individual enzyme activities to achieve 3SL target yield (61%–75%; 7–10 g/L) and overall productivity (3–5 g/L/h). Collectively, our results reveal the principal factors of enzyme cascade efficiency for 3SL synthesis and highlight the important role of engineering analysis to make multienzyme-catalyzed transformations fit for oligosaccharide production.
Original language | English |
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Pages (from-to) | 4290-4304 |
Number of pages | 15 |
Journal | Biotechnology and Bioengineering |
Volume | 118 |
Issue number | 11 |
DOIs | |
Publication status | Published - Nov 2021 |
Keywords
- 3ʹ-sialyllactose
- biocatalysis
- CMP-N-acetyl- d-neuraminic acid
- lactose
- lyase
- multienzyme cascade reaction
- N-acetyl- d-mannosamine
- N-acetyl- d-neuraminic acid (Neu5Ac)
- sialo-oligosaccharides
- synthase
- α2,3-sialyltransferase
ASJC Scopus subject areas
- Biotechnology
- Bioengineering
- Applied Microbiology and Biotechnology