Fig. 1
From: Microbial production of the plant flavanone hesperetin from caffeic acid
Microbial biosynthesis of hesperetin by whole-cell bioconversion of caffeic acid. A Hesperetin biosynthesis pathway. Enzyme abbreviations: 4CL (4-coumarate-CoA ligase), CHS (chalcone synthase), CHI (chalcone isomerase), FOMT (flavonoid O-methyltransferase). O-methylation of eriodictyol in the 4′-position yields hesperetin, whereas O-methylation in the 3′-position yields homoeriodictyol. B Construction of a combinatorial library of three flavonoid OMTs (FOMTs) using two types of origins of replication (p15A and SC101) and two varying-strength promoters (stronger promoter, Ptrc; weaker promoter, PlacUV5). C Strains producing hesperetin (orange) and homoeriodictyol (blue). To produce hesperetin and homoeriodictyol from caffeic acid, E. coli 5-alpha was cotransformed with the eriodictyol biosynthesis pathway (encoded by plasmid SBC006845) and the combinatorial library of plasmids carrying the flavonoid OMTs as illustrated in B. Error bars represent standard deviations of three biological replicates. Strains were grown in the absence (−) and presence (+) of IPTG