Probably activates the peptidyl carrier protein (PCP) domains of surfactin synthetase by transferring the 4'-phosphopantetheinyl moiety of coenzyme A (CoA) to a serine residue. Required for the production of the lipopeptide antibiotic, surfactin. apo-[peptidyl-carrier protein] + CoA = adenosine 3',5'-bisphosphate + H(+) + holo-[peptidyl-carrier protein] Belongs to the P-Pant transferase superfamily. Gsp/Sfp/HetI/AcpT family.