Lee et al. (1999) demonstrated that R3HB could be efficiently produced via in vivo
depolymerization by providing the appropriate environmental conditions. In their
study with the strain Alcaligenes latus, they found that lowering the pH to 3–4 induced
the highest activity of intracellular PHB depolymerase and blocked the reutilization of
R3HB by the cells. Ren et al. (2005) suspended PHA-containing P. putida cells in
phosphate buffer at different pH. When the pH was 11, the degradation and monomer
release was the best. Under this condition, (R)-3-hydroxyoctanoic acid and (R)-3-
hydroxyhexanoic acid were degraded with an efficiency of over 90% (w/w) in 9 h.