Fig. 1

Construction of the FFA-producing strains from S. elongatus. a Map of the aas region of the genomes of WT and the mutants. A transcriptional fusion of the nirA promoter from S. elongatus (shown in red) and the ‘tesA coding sequence from E. coli (shown in yellow) was used to replace an intragenic 662 bp fragment of the aas gene via the marker-exchange eviction method to construct dAS1T. Arrows above the map indicate the primers used for PCR analysis in b. b PCR analysis of the aas region of WT and the mutants. c Semi-quantitative RT-PCR analysis of the ‘tesA transcript in dAS1T, showing the effect of nitrogen source. Total RNA was extracted from dAS1T cells at t = 48 h and subjected to the analysis, using the rnpB transcript as a control. Cycle numbers for PCR were 24 and 26 for ‘tesA and rnpB, respectively