Digests double-stranded RNA. Involved in the processing of ribosomal RNA transcript to yield the immediate precursors to the large and small rRNAs (23S and 16S). Also processes pre-scRNA (the precursor of the signal recognition particle RNA). Probably also processes some mRNAs, and tRNAs when they are encoded in the rRNA operon (PubMed:22229825, PubMed:26940229, PubMed:11123676, PubMed:17576666, PubMed:18363798, PubMed:22412379). Probably processes pre-crRNA and tracrRNA of type II CRISPR loci if present in the organism (Probable). Involved in degradation of type I toxin-antitoxin system duplex RNAs (PubMed:22229825, PubMed:26940229). Endonucleolytic cleavage to 5'-phosphomonoester. Homodimer. Essential. Depletion leads to the accumulation of 30S precursor rRNA (PubMed:11123676), and alteration of levels of about 11% of total transcripts (PubMed:22412379, PubMed:11123676, PubMed:18363798). Increased half-life of type I toxin-antitoxin system RNAs of BsrG/SR4 and toxin BsrE mRNA (note these strains must have an essential second-site suppressor to survive) (PubMed:22229825, PubMed:26940229). Belongs to the ribonuclease III family.