Fig. 2.

pH increase is caused by high ammonia production. a pH change illustrated by the color change of the indicator (Phenol red 0.002%). LB medium alkalization after 3 and 5 days of growth of Streptomyces sp. MBT11 and S. venezuelae, no alkalization was caused by VCs produced by S. coelicolor. b Streptomyces sp. MBT11 antimicrobial VCs production curve against E. coli strain ASD19. c E. coli strain ASD19 and B. subtilis growth under different pH adjusted with glycine/NaOH buffer. d NH₃ emission. Test strips on the right compartment show the production of NH₃ by Streptomyces strains. S. coelicolor and S. lividans (∼10 mg/L); S. venezuelae (∼100 mg/L); Streptomyces sp. MBT11, and Streptomyces sp. MBT21 (∼100 mg/L); Control: SFM media (0 mg/L). Concentrations are estimated according to the color chart indicator from the Quantofix® ammonium detection Kit