Figure 1.

Effects of different nitrogen and carbon sources on biofilm formation of P. polymyxa. WLY78. (A) Biofilm formation of P. polymyxa WLY78 after cultivation in nitrogen-free medium supplemented with 200 mM glucose and 20 mM NH₄Cl for different times (h). (B) Effect of NH₄Cl concentration on biofilm biomass. (C) Effect of glutamate concentrations on biofilm biomass. (D) Effect of different carbon sources on biofilm biomass. (E) Effect of glucose concentration on biofilm biomass. (F) The relative content of each component in extracellular matrix of P. polymyxa WLY78 grown in nitrogen-free medium supplemented with 200 mM glucose and 20 mM NH₄Cl for 60–72 h. “CV” means crystal violet. Results are representative of at least three independent experiments. Error bars indicate SD. Ns indicates nonsignificant. ** indicates p < 0.01. *** indicates p < 0.001.