The invention relates to a recombinant 
engineering bacterium with the surface exhibiting and expressing 
glutamic acid decarboxylase as well as a construction method and application of the recombinant 
engineering bacterium. The preparation method mainly comprises the steps of constructing ice nucleaiton 
protein-based recombinant 
engineering bacterium with the surface exhibiting 
glutamic acid decarboxylase, inoculating a 
glutamic acid decarboxylase recombinant engineering bacterium into a culture medium, carrying out shaking culture, adding IPTG or 
lactose to induce the expression of glutamic acid decarboxylase, and collecting recombinant 
bacteria with the surface exhibiting glutamic acid decarboxylase, wherein the recombinant 
bacteria with the surface exhibiting glutamic acid decarboxylase is used for preparation of gamma-
aminobutyric acid from the substrate glutamic acid 
decarboxylation. According to the preparation method, a permeabilization treatment process required in whole-strain expression of conventionally expressed 
endoenzyme is avoided, 
recombinase is exhibited and expressed on the surface of the recombinant 
bacteria, and a substrate can be in contact with the 
recombinase to finish conversion without entering bacteria cells, so that the purpose of improving the expression activity of the recombinant bacteria is achieved. The preparation method is simple, convenient and low in cost, the operation is simple, and the expression activity of the recombinant bacteria can be efficiently improved.