p-Coumaryl alcohol derivatives have antioxidant activity.

Basis for the construction of a p-Coumaryl alcohol producing strain was the development of Operon-PLICing as method for the rapid combinatorial assembly of synthetic operons. This method is based on the chemical cleavage reaction of phosphorothioate bonds in an iodine/ethanol solution to generate complementary, single-stranded overhangs and subsequent hybridization of multiple DNA-fragments. Furthermore, during the assembly of these DNA-fragments, Operon-PLICing offers the opportunity for balancing gene expression of all pathway genes on the level of translation for maximizing product titers by varying the spacing between the Shine-Dalgarno sequence and START codon. With Operon-PLICing, 81 different clones, each one carrying a different p-Coumaryl alcohol operon, were individually constructed and screened for p-Coumaryl alcohol formation within a few days. The absolute product titer of the best five variants ranged from 48 to 52 mg/L p-Coumaryl alcohol without any further optimization of growth and production conditions.