Process Research Of Trehalose Production

Trehalose is a non-reducing disaccharide with strong stability, in which the two glucose molecules are linked with ?,?-1,1-glycosidic linkage. It can protect large bio-molecules from a variety of stress conditions. The interesting properties of trehalose made it been applied in many fields including cosmetics, pharmaceuticals, food, moisturizers, preserving agents, chaperones, stabilizer of vaccines and natural protective agent of enzymes and cells in freeze-drying conditions. Mature technology of trehalose production made it been more and more accepted by the market. In fact, the production still can't face the needing of trehalose, and new process is needed to produce more trehalose at a low expense. In the article, we made the exploration on TreS fermentation, catalytic procedure and reutilization of TreS as follows:(1) From the flask experiments, we determined original TB medium as the best fermentation medium, and find out that a lower concentration of induction agent can be used at a relative higher temperature to get a similar protein expression in comparison with inducing at lower temperature. At the same time, auto-induction was detected in TB medium. (2) The optimization of fermentation procedure, induction biomass, induction agent type, induction temperature, feeding method of induction agent and glycerol, medium modification were made in 2.5 Land 5L bioreactors. Finally an average enzyme activity of above 20000U/L was achieved after 20hrs'induction at an induction temperature of 28 ?, lactose concentration of 1.5mM, induction biomass of OD600= 20, glycerol (200g/L) feeding at a speed of 1.2g/L/h. And 60% CSL replaced TB medium can be used to reach an activity of 19000U/L in a 5L fermentation system. Finally, an enzyme activity of 16691U/L was reached in 3M3-scale industrial fermentor, shows the success production of TreS in a large scale. (3) The best addition dosage of TreS was optimized as 3U/g trehalose formation. H2O was proved to a better solvent of maltose than PBS solution, pH control of catalytic system can be used to improve the trehalose yield either. And the optimized reaction condition can be used in a 8M3 which was a large catalytic system. (4) TreS immobilization was made by modified silicalite-1 to improve the reusability of TreS, the loading dosage of total protein on silicalite-1 was 71.2%, and immobiliezed TreS can be used for more than 22 cycles with a relative activity remaining of 80%. We also postulated the possible reaction order of the trehalose decrease at post-balanced reaction.