Medium-chain-length polyhydroxyalkanoic acids (PHAmcl) produced by Pseudomonas putida IPT 046 from renewable sources

Medium-chain-length polyhydroxyalkanoates are produced by Pseudomonas putida strain IPT046 growing on carbohydrates. Analysis by gas chromatography and nuclear magnetic resonance of the elastomeric material revealed that PHA(mcl) is composed from essentially hydroxydecanoate (60-70%) and hydroxyoctanoate (20-25%) sequence units with a non-terminal double bond in about 6% of the side chains. The average molecular weight of PHA(mcl) is 223 kDalton and the X-ray diffractogram showed that 24% of the solid phase is crystalline. This biodegradable polyester presents a relative low glass transition temperature (-39.7 degreesC) and melting point (56 degreesC), is thermically stable (234 degreesC) and displays appropriate thermornechanical properties for potential use as packaging film. (C) 2003 Elsevier Science Ltd. All rights reserved.