Isolation And Identification Of Polyhydroxyalkanoates Producing Bacteria, Relevant Gene Expression In E.coli And Research Of Its Metabolic Mechanism

Polyhydroxyalkanoates (PHAs) are storage compound for carbon and energy produced by many eubacteria and some archaea. PHAs can be divided into three main types based on the sizes of the monomers incorporated into the polymer. Short-chain-length PHAs (PHAscl) consist of monomer units of C3 to C5; medium-chain-length PHAs (PHAmcl) consist of monomer units of C6 to C14, and SCL-MCL PHAs (PHAscl-mcl) consist of monomers ranging in size from C3 to C14. PHAs are biodegradable thermoplastics that have a wide variety of physical properties depending on the length of the pendant groups of the monomer units in the polymer. PHAscl are often stiff and brittle, whereas PHAmcl are elastomeric in nature. PHAscl-mcl copolymers have properties between the two states, depending on the ratio of SCL and MCL monomers in the copolymer. PHAs exhibit physical and material properties, which enable them for applications in various areas, including medicine and pharmacy. They are thermoplastic and/or elastomeric, insoluble in water, enantiomeric pure, non-toxic, biocompatible, piezoelectric and exhibit a high degree of polymerization and molecular weights of up to several million Da.Crude oil is a complicated compound containing a lot of hydrocarbons, such as alkanes and fatty acid. Crude oil and soil samples from Oilfield were collected, from which some strains that can use crude oil as carbon source were screened. Also, by using the other screen technique, we screened some bacteria with the capability to produce PHAs. It was demonstrated that some bacteria were able to grow on alkane or fatty acid as carbon source, the medium-chain-length of the PHAs were yielded. Most of the stains could be identified by traditional way and the system of Microstation which was confirmed to Pseudomonas and Bacillus. Some of the identified strains were characterized with repect to its ability to utilize...