Process for the bioconversion of fumarate to L-malate
AssigneeHuels Aktiengesellschaft
InventorFritz Schindler
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Abstract
L-malic acid is produced in a concentration of 170 to 400 g per liter and high yield by biotechnical conversion of fumaric acid neutralized with ammonium hydroxide in nutrient-free solution or suspension. Pure L-malic acid can be obtained economically therefrom with high efficiency in a quality suitable for food and pharmaceutical use. The fermentation can be carried out in simple vessels under non-sterile conditions. The conversion rate of the fumarate and the attainable concentration of L-malate are promoted by the ammonium ions.
Claims30
A process for preparing L-malate from fumarate comprising incubating under bioconversion conditions a proliferated cell mass derived from a microorganism containing fumarase effective to convert exogenous fumarate to L-malate in an aqueous solution of fumarate, said solution containing the cell mass in a concentration of from about 0.5 to 50 g/l (calculated as dry mass) and an initial fumarate concentration of about 170-400 g per liter of liquid, calculated as fumaric acid and relative to the total volume of the solution, at least half of the fumarate being in the form of ammonium-fumarate, said incubation being maintained until the yield of L-malate, calculated as L-malic acid, reaches at least 0.9 g per gram of initial fumarate, calculated as fumaric acid.
A process for producing pure L-malic acid, comprising incubating under bioconversion conditions a proliferated cell mass derived from a microorganism containing fumarase effective to convert exogenous fumarate to L-malate in an aqueous solution of fumarate, said solution containing the cell mass in a concentration of from about 0.5 to 50 g/l (calculated as dry mass) and an initial fumarate concentration of about 170-400 g per liter of liquid, calculated as fumaric acid and relative to the total volume of the solution, at least half of the fumarate being in the form of ammonium-fumarate, said incubation being maintained until the yield of L-malate, calculated as L-malic acid, reaches at least 0.9 g per gram of initial fumarate, calculated as fumaric acid, and converting the L-malate to L-malic acid and recovering said L-malic acid.
Dependencies are inferred from the claim text.