Pseudoalteromonas phenolica is a marine bacterium species in the genus Pseudoalteromonas.
Strain O-BC30 produces MC21-A (3,3â²,5,5â²-tetrabromo-2,2â²-biphenyldiol) while strain O-BC30T produces MC21-B (2,2â²,3-tribromo-biphenyl-4-4â²-dicarboxylic acid). Those two substances show antibacterial activity against methicillin-resistant Staphylococcus aureus.