Cloning and Characterization of a Sucrose Isomerase from Erwinia rhapontici NX-5 for Isomaltulose Hyperproduction
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The sucrose isomerase (SIase) gene from an efficient strain of Erwinia rhapontici NX-5 for isomaltulose hyperproduction was cloned and overexpressed in Escherichia coli. Protein sequence alignment revealed that SIase was a member of the glycoside hydrolase 13 family. The molecular mass of the purified recombinant protein was estimated at 66 kDa by SDS-PAGE. The SIase had an optimal pH and temperature of 5.0 and 30 °C, respectively, with a K m of 257 mmol/l and V max of 48.09 μmol/l/s for sucrose. To the best of our knowledge, the recombinant SIase has the most acidic optimum pH for isomaltulose synthesis. When the recombinant E. coli (pET22b- palI) cells were used for isomaltulose synthesis, almost complete conversion of sucrose (550 g/l solution) to isomaltulose was achieved in 1.5 h with high isomaltulose yields (87%). The immobilized E. coli cells remained stable for more than 30 days in a “batch”-type enzyme reactor. This indicated that the recombinant SIase could continuously and efficiently produce isomaltulose.
KeywordsErwinia rhapontici Isomaltulose Sucrose isomerase Sucrose Trehalulose
This work was supported by Key Projects in the National Science and Technology Pillar Program during the Eleventh 5-Year Plan Period (2008BAI63B07), National Natural Science Foundation of China (20906050), Natural Science Foundation of Jiangsu Province (BK2009357), The Natural Science Foundation of the Jiangsu Higher Education Institutions of China (08KJA180001), The University Nature Science Research of Jiangsu Province (09KJB530007).
- 1.Oshima, T., Izumitani, A., Sobue, S., et al. (1983). Infection and Immunity, 39, 43–49.Google Scholar
- 2.Schiweck, H., Munir, M., Rapp, K. M., et al. (1991). Schneider. In Carbohydrates as Organic Raw Materials (Ed.), Lichtenthaler, F.W (pp. 57–94). Weinheim: Wiley-VCH.Google Scholar
- 9.Cha, J., Jung, J. H., Park, S. E. et al. (2009). Journal of Applied Microbiology. dio: 10.1111/j.1365-2672.2009.04295.x
- 10.Cheetham, P. S. J. (1984). The Biochemical Journal, 220, 213–220.Google Scholar
- 18.Krastanov, A., Blazheva, D., & Stanchev, V. (2007). Process Biochemistry, 42, 1655–1659.Google Scholar
- 21.Xu, H., Li, S., Huang, M. X. et al. (2007). CN patent 200710190755.2.Google Scholar