Recombinant lactococcus lactis for secretory expression of swine-derived anti-enterotoxigenic escherichia coli K88 pilus single-chain antibody and preparation method of recombinant lactococcus lactis

The invention relates to recombinant lactococcus lactis for secretory expression of a swine-derived anti-enterotoxigenic escherichia coli K88 pilus single-chain antibody and a preparation method of the recombinant lactococcus lactis, and belongs to the technical field of genetic engineering. The recombinant lactococcus lactis carries a fusion sequence for secretory and expression of an anti-enterotoxigenic escherichia coli K88 pilus single-chain antibody. The fusion sequence has a sequence as shown in SEQ ID No. 1 and a single-chain antibody sequence as shown in SEQ ID No. 2, wherein the sequence as shown in SEQ ID No. 1 is a sequence containing a secretion signal peptide USP45, a secretion enhancing signal peptide LEISSTCDA and a thioredoxin gene. The molecular weight of the obtained secreted single-chain antibody for resisting enterotoxigenic escherichia coli K88 pilus is about 45kDa, and the secreted single-chain antibody can specifically recognize enterotoxigenic escherichia coli,block bacterial infection