Enhancing expression of recombinant fimbrial adhesin K88 isolated of enterotoxigenic Escherichia coli from piglet

Abstract

Fimbrial adhesins are important toxic factors of enterotoxigenic E. coli (ETEC) strains, whereby they have the ability to adhere to small intestine of the host. K88 (F4) is the first fimbrial adhesin was detected in ETEC strains from piglet, and it is the most popular fimbrial adhesin of E. coli strains causes diarrhea in weaned piglets. In previous report, we successful expressed the faeG gene encoding fimbrial adhesin K88-1NT in recombinant E. coli BL21 (DE3). Highest level of K88-1NT was determined after induction by 0.1% lactose for 6 h at 35^oC when cell density (OD₆₀₀) reached a value of 0.5. Induction medium including Na₂HPO₄.12H₂O 1%, KH₂PO₄ 0.3%, NaCl 0.05%, (NH₄)₂SO₄ 1%, MgSO₄.7H₂O 0.2%, glucose 1.5%, tryptone 1% and yeast extract 1%. Purified K88-1NT protein from Ni²⁺ affinity chromatography had a molecular weight of 31 kDa.