| 摘要 |
Transgenic microbial strains are provided which contain the genes required for PHA formation integrated on the chromosome. The strains are advantageous in PHA production processes, because (1) no plasmids need to be maintained, generally obviating the required use of antibiotics or other stabilizing pressures, and (2) no plasmid loss occurs, thereby stabilizing the number of gene copies per cell throughout the fermentation process, resulting in homogeneous PHA product formation throughout the production process. Genes are integrated using standard techniques, preferably transposon mutagenesis. In a preferred embodiment wherein mutiple genes are incorporated, these are incorporated as an operon. Sequences are used to stabilize mRNA, to induce expression as a function of culture conditions (such as phosphate concentration), temperature, and stress, and to aid in selection, through the incorporation of selection markers such as markers conferring antibiotic resistance.
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