Biosynthesis of Medium-chain-length Poly(hydroxyalkanoates) from Soy Molasses

Pseudomonas corrugata was selected from a screening process for the bioconversion of inexpensive soy molasses into medium-chain-length poly(hydroxyalkanoates) (mcl-PHA). We obtained yields of 1.5 g cell dry weight (CDW)/l culture with growth medium supplemented with 2% (w/v) soy molasses, and of an average of 3.4 g CDW/l with 5% (w/v) soy molasses. Crude PHAs were obtained at 5–17% of CDW. The most prominent repeat-unit monomers in the PHAs were 3-hydroxydodecanoate, 3-hydroxyoctanoate, 3-hydroxydodecanoate, and 3-hydroxytetradecenoate. This work represents the first description of fermentative mcl-PHA production from the soy molasses.