Isolation and Characterization of a <i>Bacillus amyloliquefaciens</i> Bacteriophage JBA6 and Its Endolysin PlyJBA6

<i>Bacillus amyloliquefaciens</i> is a Gram-positive, aerobic, spore-forming bacteria usually found in soil. Despite its probiotic potential, <i>B. amyloliquefaciens</i> has been identified as a cause of food spoilage, including the development of off-odors, rope formation, and the production of viscous substances in a wide range of foods. To control <i>B. amyloliquefaciens</i>, we isolated three <i>B. amyloliquefaciens</i> bacteriophages TBA3, JBA3, JBA6, and characterized one representative JBA6 endolysin, PlyJBA6. Transmission electron microscopy and genomic analysis demonstrated that all three phages belong to the <i>Salasmaviridae</i> family, characterized by short, non-contractile tails with linear dsDNA genomes ranging from 18.7 to 19.1 kb. PlyJBA6 contains a glycoside hydrolase family 24 domain (PF00959) at the N-terminus and two LysM domains (PF04176) at the C-terminus. While JBA6 has a narrow host range, infecting only 7 out of 9 tested strains of <i>B. amyloliquefaciens</i>, PlyJBA6 exhibits extended lytic range beyond the <i>Bacillus</i> genus. Interestingly, PlyJBA6 lyses Gram-negative bacteria such as <i>Escherichia coli</i>, <i>Yersinia enterocolitica</i> and <i>Cronobacter sakazakii</i> without other additives to destabilize bacterial outer membrane. We assume that JBA6 might be a useful component for a phage cocktail to control <i>B. amyloliquefaciens</i> and that PlyJBA6 can provide insights into the development of novel biocontrol agents against various food-borne pathogens.