Promoter activities per cell characterized using an EYFP reporter construct carried on pPMQAK1 in Synechocystis PCC 6803. A. Native promoters from Synechocystis included for comparison. PnirA is the nitrate reductase promoter, PpetE is the plastocyanin promoter and PrnpB is the RNase P subunit B promoter. B. Minimal constitutive promoters from an Escherichia coli synthetic promoter library. The J23### promoters correspond to the BBa_J23### BioBrick parts obtained from the iGEM Registry . Promoter activities per cell are given in fluorescence/absorbance at 750 nm in arbitrary units [AU]. Error bars indicate standard error of the mean (n = 6).