Formation of L-malic acid by yeasts of the genus Dipodascus

The yeast strains of the genus Dipodascus were used for the bioconversion o f fumaric acid to L-malic acid. Under nongrowth conditions, the fumarase ac tivity in the intact cells or in the cell-free extract of Dipodascus was 10 times higher than that of Saccharomyces cerevisiae cells. Pretreatment of the Dipodascus with malonate was not necessary because succinate was not de tected as a by-product. The fumarase activity in Dipodascus magnusii CCM 82 35 was increased approximately 100% when Triton X-305 (0.1%) was added to t he reaction mixture.