In 1986 it was believed that the P(3HB) in granules waspresent as a crystalline solid, so the observation (usingsolution state NMR) that P(3HB) in live cells was in anamorphous state was unexpected [149–152]. It was foundthat treating the cells to deactivate the granules also ledto a loss of high resolution in the NMR spectrum, with thesimultaneous appearance of crystalline P(3HB), as judgedby X-ray diffraction (XRD). Purified PHAs and even isolatedPHA granules are known to crystallize rapidly under someconditions. This suggests an important role for the granulesurface layer in preventing crystal nucleation [19,112].