A recombinant lipoprotein antigen against Lyme disease expressed in E-coli: Fermentor operating strategies for improved yield

Decorin-binding lipoprotein, lpp-DBP, a bacterial surface adhesin, shows pr omise as a vaccine against Lyme disease. It is expressed in recombinant E. coli as an undesirable 20.5 KDa apoprotein that is subsequently lipidated i n vivo to the desired 22 KDa lpp-DBP form. This study defines fermentation conditions for maximizing Ipp-DBP yield Super broth medium, a low post-indu ction temperature (30 degrees C), and a glucose feed based on dissolved oxy gen resulted in high Ipp-DBP yield and minimized apoprotein formation. Sinc e cells lysed within 2-3 h after induction, the cell yield was maximized by growing cells to high cell density prior to induction. Compared to a gluco se feed based on maintaining a constant fermenter glucose concentration (Gl ucose-Stat), feeding based on maintaining a constant dissolved oxygen level (DO-Stat) improved yields. Also, a dissolved oxygen level of 60% (air satu ration) was best, as no product degradation was detected by Western blottin g and SDS-PAGE. Acetic acid levels under both modes of glucose feed were su fficiently low, and no adverse growth effects were observed.