Threonine dehydrogenase gene mutant and application thereof

The invention discloses a threonine dehydrogenase gene mutant and application thereof, belongs to the technical field of biology, and aims to solve the technical problem of how to improve the yield of microorganisms L-valine or L-isoleucine. In particular, the present invention discloses an engineered threonine dehydrogenase comprising a mutation in the amino acid at position 131, 171 or 218 relative to a reference sequence (SEQ ID No.2). Recombinant bacteria for overexpressing ilvAV131A, ilvAR171H and/or ilvAM218I genes and point mutation recombinant bacteria are constructed, and results show that overexpression of mutant genes can improve the yield of L-valine and/or L-isoleucine of recipient bacteria, and has the effect of synergistically promoting production of L-valine and/or L-isoleucine, so that the recombinant bacteria can be used for preparing the recombinant bacteria for treating L-valine and/or L-isoleucine, and the recombinant bacteria can be used for preparing the recombinant bacteria for treatin