Malacidin B is a homodetic cyclic peptide that is malacidin A in which the (2E,4Z)-8-methylnona-2,4-dienoyl group has been replaced by a (2E,4Z)-8-methyldeca-2,4-dienoyl group. It has a role as a bacterial metabolite, a member of calcium-dependent antibiotics and an antibacterial agent. It is a homodetic cyclic peptide and a lipopeptide.