Involved in acetate metabolism. In combination with LdhA and AckA, allows fermentation of pyruvate, enhancing long-term survival under anaerobic conditions. acetyl-CoA + phosphate = acetyl phosphate + CoA Activity is increased under anaerobic growth conditions. Metabolic intermediate biosynthesis; acetyl-CoA biosynthesis; acetyl-CoA from acetate: step 2/2. Homohexamer. The ackA-pta operon is induced under oxygen-limiting conditions by the oxygen regulator Anr and DNA-binding integration host factor. The N-terminal region seems to be important for proper quaternary structure. The C-terminal region contains the substrate-binding site (By similarity). Decreased survival under anaerobic conditions. In the N-terminal section; belongs to the CobB/CobQ family. In the C-terminal section; belongs to the phosphate acetyltransferase and butyryltransferase family.