(2R,3S,4R,5R)-2,3,4,5,6-pentahydroxyhexanal → beta-Maltose

Participants

Reaction Steps

Into a fermenter was poured a liquid nutrient culture medium consisting of 2 w/v % glucose, 0.5 w/v % polypeptone, 0.1 w/v % yeast extract, 0.1 w/v % dipotassium phosphate, 0.06 w/v % sodium dihydrogen phosphate, 0.05 w/v % magnesium sulfate, 0.5 w/v % calcium carbonate, and water, and the medium was sterilized by heating, cooled and inoculated with a seed culture of Pimelobacter sp. R48 (FERM BP-4315), followed by the incubation at 27° C. for about 40 hours under stirring conditions. The resultant culture had 0.55 units/ml of a maltose-trehalose converting enzyme. 0.18 kg of wet cells collected from 18 L of the culture was suspended in 10 mM phosphate buffer (pH 7.0), and about 1.5 L of the suspension was treated with an ultrasonic cell disrupter to disrupt cells. The resultant mixture was centrifuged to obtain a supernatant which was then concentrated with a UF membrane to obtain an about 500 ml of a concentrated enzyme solution containing about 18 units/ml of a maltose-trehalose converting enzyme. To 15% corn starch suspension (pH 5.5) was added 2 units/g starch, d.s.b., of "SPITASE HS", α-amylase commercialized by Nagase Biochemicals, Ltd., Kyoto, Japan, and the mixture was stirred, heated to effect gelatinization and liquefaction, and then promptly autoclaved at 120° C. for 20 min. Thereafter, the resultant mixture was cooled to 55° C., adjusted to pH 5.0, mixed with 300 units/g starch, d.s.b., of isoamylase, 20 units/g starch, d.s.b., of β-amylase commercialized by Nagase Biochemicals, Ltd., Kyoto, Japan, and enzymatically reacted for 24 hours to obtain an about 92% maltose solution. The solution thus obtained was heated at 100° C. for 20 min, cooled to 20 ° C., adjusted to pH 7.0, and mixed with 1.5 units/g starch, d.s.b., of the concentrated enzyme solution prepared in the above, and enzymatically reacted for 72 hours. The resultant reaction mixture was heated at 95° C. for 10 min, cooled, and, in usual manner, decolored with an activated charcoal, filtered, desalted and purified with ion-exchangers in H--and OH-form, and concentrated into an about 50% syrup.

Provenance & Evidence