Fig. 1.

Module design of a lactic acid bacterium-based drug delivery system for optimal P8 productivity. a A schematic outline depicting the expected mode of action of the synthetic probiotic PP*-P8 with the alr complementation system. alr, the alanine racemase gene. b Constructs with various promoters for dual expression of the P8 therapeutic protein fused to the 27-residue Usp45 leader peptide. GK, glucose kinase; LDH, l-lactate dehydrogenase; PK, pyruvate kinase; ChoS, choline ABC transporter permease and substrate binding protein. c Concentrations of P8 secreted from PP*-P8 that were quantified using ELISA, indicating that the PK-PK promotor system had the highest amount of secreted P8