Involved in the biosynthesis of 2-methyl-3-n-amyl-pyrrole (MAP), one of the terminal products involved in the biosynthesis of the red antibiotic prodigiosin (Pig). Catalyzes the decarboxylation of pyruvate, followed by the modification of the resulting two-carbon fragment acetaldehyde at the C3 position of the 2-octenal (1,2-addition of acetaldehyde) giving 3-acetyloctanal. (2E)-octenal + H(+) + pyruvate = (S)-3-acetyloctanal + CO2 Antibiotic biosynthesis; prodigiosin biosynthesis. Cells lacking this gene show a white phenotype and produce 4-hydroxy-2,2'-bipyrrole-5-carbaldehyde (HBC), 4- methoxy-2,2'-bipyrrole-5-carbaldehyde (MBC) and 4-hydroxy-2,2'-bipyrrole-5-methanol (HBM). Belongs to the TPP enzyme family.