The latest work of the Bressler et al. [20] includes the biotransformation
of fumaric to l-malic acid by immobilized yeast
engineered to overproduce fumarase. In order to achieve a higher
conversion this reaction was performed in a specific bioreactor
that was divided into three compartments (feed, reaction and
product) by two supported liquid membranes. The first membrane
(between feed and reaction) was selective toward the
substrate (fumaric acid), while the other one (between product
and reaction) was selective toward the l-malic acid. Recently,
in our lab we tested several commercial yeast strains. In order
to achieve higher activity of the yeast cells we optimized the