Table 2.

Rhamnolipid production and swarming as a function of the amino acid provided as the sole nitrogen sourcea

Amino acidSwarmingRhamnolipid
Alanine±±
Arginine
Asparagine
Aspartate++++
Cysteine±+
Glutamine±
Glutamate++++
Glycine+±
Histidine++++
Isoleucine+++
Leucine+
Lysine±++
Methionine
Phenylalanine+
Proline++
Serine±+
Threonine+
Tryptophan+
Tyrosine+
Valine++
  • a Swarming and rhamnolipid production were determined as described in Materials and Methods on M8-based minimal medium plates with glucose as the carbon source and supplemented with the indicated amino acid at a final concentration of 0.05%. Swarm plates were incubated for 24 h at 37°C, while rhamnolipid production was scored after incubation for 24 h at 37°C and 24 h at room temperature. −, not detected; ±, weak; +, intermediate; ++, strong.