Catalyzes the deacetylation of N-acetylmuramic acid (MurNAc) residues in glycan strands of peptidoglycan, leading to the formation of muramic delta-lactam residues in spore cortex, after transpeptidation of deacetylated muramic acid residues. PdaA probably carries out both deacetylation and lactam ring formation and requires the product of CwlD activity on peptidoglycan as a substrate. Is required for germination. Cannot use chitin oligomer (hexa-N-acetylchitohexaose) as a substrate. Optimum pH is 7.0. Expressed in the forespore, then exported into the developing cortex. Expression is sigma G-dependent. Spores have no muramic delta-lactam structure in the cortex and cannot germinate. Mutant spore peptidoglycan possesses many MurNAc residues lacking peptide side chains. CwlD and PdaA are necessary and sufficient for muramic delta-lactam production in B.subtilis spore peptidoglycan. Belongs to the polysaccharide deacetylase family.