beta-Maltose → Trehalose

Participants

Reaction Steps

A seed culture of Pseudomonas putida H262 (FERM BP-4579) was culture in a nutrient culture medium similarly as in Experiment 9, and the resultant cells were recovered by centrifugation to obtain 100 g wet cells having a maltose-trehalose converting enzyme activity of about 400 units which were then kneaded with 100 ml of 10 mM phosphate buffer in which 2.5% sodium alginate having a viscosity of 300-400 cp had been dissolved. The slurry containing the cells were continuously dropped into 0.1 M CaCl2 solution stirred by a magnetic stirrer from a height of about 20 cm above the surface of the solution to form spherical gels having a diameter of about 2 mm. The gels were kept in the CaCl2 solution at ambient temperature for about 2 hours, filtered with a Buchner funnel to obtain cells immobilized with sodium alginate. The immobilized cells were packed in a jacketed glass-column having a diameter of 30 mm and a length of 200 mm and kept at 35° C. The column was fed with a downstream of 40% maltose solution (pH 6.8) at SV 0.1 to obtain a 67% trehalose solution. In accordance with the method in Example A-9, the trehalose solution was purified, concentrated, crystallized, and spray dried to obtain a massecuite-type hydrous crystalline trehalose powder in a yield of about 90%, d.s.b. The product has a relatively-low reducing power, a mild sweetness and an adequate moisture-retaining ability, and because of these it can be arbitrarily used as a variety of compositions similarly as the product in Example A-9.

Provenance & Evidence