Efficient production of isomaltulose using engineered Yarrowia lipolytica strain facilitated by non-yeast signal peptide-mediated cell surface display.

Background: Isomaltulose is a 'generally recognized as safe' ingredient and is widely used in the food, pharmaceutical and chemical industries. The exploration and development of efficient technologies is essential for enhancing isomaltulose yield.
Results: In the present study, a simple and efficient surface display platform mediated by a non-yeast signal peptide was developed in Yarrowia lipolytica and utilized to efficiently produce isomaltulose from sucrose. We discovered that the signal peptide SP1 of sucrose isomerase from Pantoea dispersa UQ68J (PdSI) could guide SIs anchoring to the cell surface of Y. lipolytica, demonstrating a novel and simple cell surface display strategy. Furthermore, the PdSI expression level was significantly increased through optimizing the promoters and multi-site integrating genes into chromosome. The final strain gained 451.7 g L ^-1 isomaltulose with a conversion rate of 90.3% and a space-time yield of 50.2 g L ^-1  h ^-1 .
Conclusion: The present study provides an efficient way for manufacturing isomaltulose with a high space-time yield. This heterogenous signal peptide-mediated cell surface display strategy featured with small fusion tag (approximately 2.2 kDa of SP1), absence of enzyme leakage in fermentation broth and ample room for optimization, providing a convenient way to construct whole-cell biocatalysts to synthesize other products and broadening the array of molecular toolboxes accessible for engineering Y. lipolytica. © 2024 Society of Chemical Industry.
(© 2024 Society of Chemical Industry.)