3.4.8. Fatty-Acid Biosynthesis

Two mutations were observed in biofilm population 1 with roles in fatty-acid biosynthesis. A mutation in fatty-acid metabolism transcriptional regulator FadR was observed on days 24 and 36, which corresponded to 256- and 1024-fold increases in MIC from baseline. This gene activates fatty-acid synthesis while repressing fatty-acid degradation in response to environmental fatty-acid levels and may influence bacterial cell size [41]. A mutation in acyl carrier protein ACP was generated and fixed after day 24 and aligned with a 246–1024-fold increase in MIC (Table 4). ACP is a highly conserved transport protein for acyl intermediates and is necessary for fatty-acid biosynthesis [42]. Mutations in *fadR* and *acpP* aligned with the timing of a mutation in *pqqC*, which affects energy metabolism, and a mutation in *qseC*, which has roles in biofilm formation (Figure 4).
