Figure 3.

Effect of l-arginine on planktonic growth (a) and biofilm formation (b) by P. putida KT2440. Cultures were grown in 96-well plates in FAB medium with glucose and different concentrations of l-arginine (0, 5 and 15 mM). Growth was measured at 660 nm, and attached biomass was quantified as absorbance at 595 nm after staining with crystal violet (CV) and subsequent solubilisation of the dye. Results are averages and standard errors of two independent experiments with four technical replicates each. Asterisks indicate statistically significant differences with respect to the control without l-arginine (Student’s t test; p ≤ 0.05).