A process for treating a mixture of R,R- and S,S-lactide is provided. The process involves contacting the lactide mixture with an aliphatic alcohol and/or an alkoxide to produce a mixture of R,R- and S,S-aliphatic ester of lactyllactic acid, subsequently contacting the mixture of R,R- and S,S-aliphatic ester of lactyllactic acid with an enzyme to produce a mixture comprising aliphatic ester of lactic acid corresponding to one lactide enantiomer and the aliphatic ester of lactyllactic acid corresponding to the other lactide enantiomer, and recovering the product. Also provided are processes for the production of S-lactic acid, S,S-lactide, poly-S-lactic acid, R-lactic acid, R,R-lactide, poly-R-lactic acid and stereocomplex polylactic acid.