Molecular weight distribution of native poly(D‐β‐hydroxybutyric acid)

The molecular weight distribution of the biopolyester 1 from D ‐β‐hydroxybutyric acid, isolated from Rhizobium meliloti by methods which preserved its native molecular properties, was studied. The weight average degree of polymerization is approximately DP w =23000, 1 being therefore one of the highest biopolymers with respect to chain length. The distribution of the degree of polymerization of 1 is distinguished by a great homogeneity, which it still possesses even after 30 hours of synthesis. One can conclude, therefore, that biosynthesis of an endogeneous bacterial polymer like 1 takes place also by a mechanism which produces molecules of homogeneous chain length, as e.g. a Possion type mechanism, and where the mean time of synthesis coincides approximately with the mean time of generation.