Sulfuric Acid → L-Malic Acid

Participants

Reaction Steps

30 g of the immobilized preparation of Brevibacterium ammoniagenes IAM 1645, obtained in the same manner as described in Example 1-(1), are suspended in 100 ml of an aqueous 1 M sodium fumarate solution (pH 7.5) containing 3 mg/ml of ox bile extract (manufactured by Inolex Pharmaceutical Division Wilson Pharmaceutical & Chemical Corporation, Illinois, U.S.A.). The suspension is allowed to stand at 37° C. for 20 hours, and is then filtered. The immobilized preparation thus obtained is washed with a physiological saline solution and charged into a column (2.2 cm×19.5 cm). One liter of an aqueous 1 M sodium fumarate solution(pH 7.5) is passed through the column at 37° C. at a flow rate of 20 ml/hr. The effluent is acidified with 200 ml of concentrated hydrochloric acid, and then filtered to remove the precipitates of fumaric acid. The filtrate is adjusted to pH 6.0 with about 70 g of calcium hydroxide. The crystalline precipitates are collected by filtration, washed with water and then dried. 150 g of calcium L-malate dihydrate are thereby obtained. 350 ml of 2N-sulfuric acid are added to calcium L-malate dihydrate. The mixture is filtered to remove the precipitates. The filtrate is passed through a column charged with about 150 ml of Amberlite IR-120(H+ type) and then passed through a column charged with about 150 ml of Amberlite IR-45 (OH- type). The effluent is concentrated at 60° C. under reduced pressure. The crystalline precipitates are collected by filtration, washed with a small amount of acetone and then dried. 50 g of L-malic acid are thereby obtained. The mother liquor is concentrated and the concentrated solution is treated in the same manner as above. 22 g of L-malic acid are thereby obtained. Total amount 77 g M. P. 100° C. [α]D20 =-2.2°(C=8.5, H2O)

Provenance & Evidence