On the preparation of methyl and ethyl (r)-(−)-3-hydroxy-valerate by depolymerization of a mixed phb/phv biopolymer

The microbial polyester containing 70–80% 3-hydroxy-butanoate and 20–30% 3-hydroxy-pentanoate (PHB/PHV, 2) is depolymerized to give monomeric esters of (R)-configuration. These are separated by fractional distillation. (R)-3-Hydroxy-pentanoate (4) is thus made readily available as enantiomerically pure starting mortal for synthesis.