Isomaltulose production by yeast surface display of sucrose isomerase from Pantoea dispersa on Yarrowia lipolytica

- A Y. lipolytica strain displaying sucrose isomerase was constructed.
- The Y. lipolytica cells converted sucrose to isomaltulose at a yield of 93 ± 2%.
- The sucrose isomerase displayed on yeast cell wall was more stable than its free form.
- No trehalulose or glucose by-products were detected in the transformation.

The gene encoding for sucrose isomerase from Pantoea dispersa (PdSIase) was successfully displayed on the cell surface of Yarrowia lipolytica, using the cell wall protein Pir1 as an anchor protein. The highest isomaltulose conversion yield of 93 ± 2% was obtained using the displayed PdSIase. The yeast strain displaying PdSIase was stable throughout broad ranges of pH values (4.5-7.0) and temperatures (20-40 °C). In addition, no trehalulose or glucose by-products were detected during the transformation process. The yeast cells remained highly viable in repeated batch operations for 12 cycles, with a high conversion yield of no less than 80%. The results in our study demonstrate that the PdSIase displayed by Y. lipolytica could continuously and efficiently convert sucrose to isomaltulose.