Aspartyl-phosphate phosphatase which specifically dephosphorylates the sporulation transcription factor Spo0A-P and negatively regulates the sporulation initiation pathway in order to control the proper timing of sporulation. Interacts with Spo0A. Probably degraded by FtsH, the last 14 residues seem to form the FtsH recognition site. Mutations that block the onset of sporulation in Bacillus subtilis are called stage 0 mutations, or spo0 mutations, and at least eight genetic loci have been identified in which a mutation can result in a stage 0 phenotype. Stage 0 mutants lack the ability to form the asymmetric septum characteristic of the initiation of the sporulation process. In addition, these mutations have many pleiotropic effects on the synthesis of a variety of transcripts by minor forms of RNA polymerase in this organism. Belongs to the spo0E family.