A number of Pseudomonas strains accumulated polyhdroxyalkanoate (PHA) from a variety of aromatic hydrocarbons. In many strains the level of PHA accumulation was dependent on the side chain length of the phenylalkanoic acid provided for growth. 4 of the 8 strains accumulated increased levels of PHA as the side chain length of the phenylalkanoic acid substrate increased. PHA accumulated from styrene and phenylacetic acid was composed of aliphatic monomers only. The PHA accumulated from any one of the phenylalkanoic acids with 5 carbons or more in their side chain (n>or=5) was almost identical for all strains with PHA composed of both aromatic and aliphatic monomers. The predominant monomers accumulated were 3-hydroxyphenylvaleric acid and 3-hydroxyphenylhexanoic acid. The addition of the metabolic pathway inhibitors acrylic acid and 2-bromoctanoic acid resulted in decreased levels of PHA from phenylacetic acid, suggesting a role for both beta-oxidation and fatty acid synthesis in PHA accumulation from phenylacetic acid.