Transformed microorganism for producing PHA copolymer comprising 3HH monomer unit at high composition rate and method for producing PHA using same

A transformed microorganism that is a bacterium belonging to the genus Cupriavidus, comprising:

• a PHA synthase gene capable of synthesizing a polyhydroxyalkanoate (PHA) copolymer comprising 3-hydroxyhexanoate (3HH) monomer unit and 3-hydroxybutanoate (3HB) monomer unit;
• and
• a gene encoding a protein having (R)-specific enoyl-CoA hydratase activity,
• wherein in the transformed microorganism, at least two genes encoding a β-ketothiolase enzyme are disrupted such that the activity of the β-ketothiolase enzyme having thiolysis activity for β-ketohexanoyl-CoA is reduced or lost as compared to a corresponding non-transformed microorganism, resulting in increase in a 3HH ratio in a PHA copolymer produced in the transformed microorganism compared to that in a non-transformed microorganism,
• wherein a phaA gene is not disrupted in the transformed microorganism, and
• wherein the at least two genes encoding the β-ketothiolase enzyme is a combination of the gene (i) and gene (ii):
• (i) a bktB gene comprising the nucleotide sequence of SEQ ID NO:
• 7, or a nucleotide sequence having 85% or higher sequence identity to the nucleotide sequence of SEQ ID NO:
• 7;
• and
• (ii) an A1528 gene having comprising the nucleotide sequence of SEQ ID NO:
• 8, or a nucleotide sequence having 85% or higher sequence identity to the nucleotide sequence of SEQ ID NO:
• 8.