Figure legends
Fig. 1. Biosynthetic routes for converting l-lysine to l-pipecolic acid via P2C and P6C pathways.
Fig. 2. Construction of the pipecolic acid production system with expression combination. (a) Selection of expression vectors and (b) selection of expression strains.
Fig. 3. Comparison between single gene and tandem gene expression with two-vector system. yhPA001 (pCDF duet-1::pipA ), yhPA002 (pET duet-1::pipA ), yhPA003 (pCDF duet-1::pipA + pET duet-1::pipA ), yhPA004 (pCDF duet-1::pipA ::pipA ), yhPA005 (pET duet-1::pipA ::pipA ), and yhPA006 (pCDF duet-1::pipA ::pipA + pET duet-1::pipA ::pipA ) were used.
Fig. 4. Optimization of culture conditions affecting enzyme activity: (a) relative enzyme activity with different media, (b) cell dry weight with different media, (c) induction temperature, and (d) IPTG concentration.
Fig. 5. Effect of (a) agitation, (b) buffer concentration, (c) metal ions, and (d) iron source on whole-cell bioconversion
Fig. 6. Pipecolic acid production according to l-lysine concentration. (a) Time-dependence of pipecolic acid production (b) Production and conversion at the highest point for each.