3'-5' exoribonuclease that releases 5'-nucleoside monophosphates and is involved in maturation of structured RNAs (By similarity). Involved in degradation of type I toxin-antitoxin system bsrG/SR4 RNAs (PubMed:22229825). Exonucleolytic cleavage in the 3'- to 5'-direction to yield nucleoside 5'-phosphates. Constitutively expressed, part of a 5 gene operon with multiple promoters. Not ethanol-stress induced. No visible phenotype (PubMed:17369301). Increased half-life of type I toxin-antitoxin system RNAs of BsrG/SR4 (PubMed:22229825). Belongs to the RNR ribonuclease family. RNase R subfamily.