Fig. 2
Schematic representation of the combinatorial construction of the naringenin biosynthesis pathway. For every catalytic step in the pathway, libraries are created on carrier plasmids, each library variant being composed of one out of ten different σB-specific promoters and one out of two different enzyme variants. All carrier plasmid inserts are subsequently assembled in a predefined order in a single reaction, generating a pathway library [34]. (TIF transcription initiation frequeny, σ sigma factor)