Recombinant thermophilic enzymes for trehalose and trehalosyl dextrins production

Two thermophilic and thermostable enzymes, trehalosyl dextrins forming enzyme (TDFE) and trehalose forming enzyme (TFE), able to convert starch and dextrins to ,-trehalose were recently purified and characterized from Sulfolobales [I. Di Lernia, A. Morana, A. Ottombrino, S. Fusco, M. Rossi, M. De Rosa, Extremophiles, 2 (1998) 409; T. Nakada, S. Ikegami, H. Chaen, M. Kubota, S. Fukuda, T. Sugimoto, M. Kurimoto, Y. Tsujisaka, Biosci., Biotechnol., Biochem., 60 (1996) 267; T. Nakada, S. Ikegami, H. Chaen, M. Kubota, S. Fukuda, T. Sugimoto, M. Kurimoto, Y. Tsujisaka, Biosci., Biotechnol., Biochem., 60 (1996) 263; M. Kato, Y. Miura, M. Kettoku, K. Shindo, A. Iwamatsu, K. Kobayashi, Biosci., Biotechnol., Biochem., 60 (1996) 921; M. Kato, Y. Miura, M. Kettoku, K. Shindo, A. Iwamatsu, K. Kobayashi, Biosci., Biotechnol., Biochem., 60 (1996) 925]. The first enzyme transforms starch and dextrins to the corresponding trehalosyl derivatives, with an intramolecular transglycosylation process, which converts the glucosidic linkage at the reducing end from -1,4 to -1,1. The second, hydrolyzes the -1,4 linkage adjacent to the -1,1 bond of trehalosyl dextrins, forming trehalose and lower molecular weight dextrins. Herein, we report the cloning and high level expression of the two enzymes of Sulfolobus solfataricus strain MT4 in Escherichia coli using pTrc expression vector. The yield of TDFE and TFE obtained in this expression system was of 180 U/l and of 3630 U/l of medium, respectively.