The invention discloses an
engineering bacterium for efficiently synthesizing
pyruvic acid and D-
alanine and a construction method and application of the
engineering bacterium. On the basis of a
genetic engineering strain BLK07 (pET20b-pm1), a strain with improved
enzyme activity of pm1 is screened out through site-saturation
mutagenesis, and an N-terminal encoding sequence (NCS) is inserted intoan N terminal of a
gene sequence of the pm1, so that the
protein expression quantity of the pm1 is improved, the yield of the
pyruvic acid is increased, the catalytic time is significantly shortened and the
catalytic efficiency is improved. When the concentration of substrates D-
alanine and L-
alanine is 110 g / L, the
cell concentration is 4 g / L and a catalyst
system only carries out
catalysis at 37DEG C and 220 rpm in a
shake flask for 8 h, the yield of the
pyruvic acid can reach a maximum value 46.5 g / L, the conversion rate of the L-alanine is 84.5% and the
resolution rate of the D / L-alaninereaches 84.5%.