Complete genome analysis and biological characterization of phage vB_Bsu_hmny2 infecting Bacillus subtilis

Bacillus subtilis, a key microorganism in food fermentation, is frequently compromised by phage contamination, which can result in fermentation failures. Therefore, understanding and controlling B. subtilis-infecting phages is critical for enhancing fermentation stability. In this study, we characterized a novel lytic B. subtilis phage, vB_Bsu_hmny2, isolated from sewage collected at a seafood market in Qingdao, China. This phage has a linear double-stranded DNA genome of 18,762 bp with 25 open reading frames (ORFs), the functions of 17 of which were predicted. Transmission electron microscopy examination revealed that the phage exhibits podovirus morphology, with a head measuring 40 ± 10 nm in diameter and a short tail measuring 20 ± 6 nm in length. vB_Bsu_hmny2 exhibited stability across a range of temperatures and pH levels and was found to belong to the species Beecentumtrevirus Nf in the family Salasmaviridae. vB_Bsu_hmny2 is the first phage of the genus Beecentumtrevirus to undergo physiological characterization. This research addresses a gap in the functional analysis of phages, providing valuable insights for phage control in industrial fermentation processes.