The optical purity of
lactic acid is crucial for the physical properties of
PLA. Though L-lactic acid can be polymerized to
give crystalline (PLLA) suited to commercial uses
(Sodegard and Stolt 2002), its application is limited
by its low melting point. Complexing PLLA with
poly D-lactic acid (PDLA), however, increases the
melting point thus presenting an attractive solution to
the heat sensitivity of PLA (Tsuji and Fukui 2003).
This finding has increased the importance of the
synthesis of D-lactic acid. Presently, L-lactic acid is
widely used in the food and pharmaceutical industries
and hence its production by fermentation is well
established