L-malic acid production by entrapped Saccharomyces cerevisiae into polyacrylamide gel beads.

The yeast Saccharomyces cerevisiae was entrapped within polyacrylamide gel beads by employing a procedure that uses sodium dodecylsulfate as a detergent to improve the spherical configuration of the beads. The resulting preparation showed a rate of fumarate bio-conversion to L-malic acid about 60 times higher than that found for the free cells. Almost all fumarate was converted in 30 min of incubation. The thermal stability of the immobilized cells did not significantly differ from the free cells. An optimal pH of 5.7 was found for the immobilized preparation and no succinic acid was detected as a byproduct in the incubation mixture.

L-malic acid production using immobilized Saccharomyces cerevisiae.

L-Malate was produced from fumarate by using immobilized Saccharomyces cerevisiae cells entrapped in polyacrylamide. This preparation performed better when pretreated with malonate. Under the experimental conditions described here, succinate was not detected as a by-product of the reaction, as had been reported for other microorganisms.