Occurrence of bacteriophages lytic for Pediococcus halophilus, a halophilic lactic-acid bacterium, in soy sauce fermentation.

Abstract

Bacteriophages specific for Pediococcus halophilus, a group of halophilic lactic cocci used as starters for soy sauce fermentation, were isolated from fermenting soy sauce moromi-mash. Typical two of these phages, φ7116 and φD-86, which propagate on P. halophilus NISL 7116 and D-86 respectively, were purified and studied for their morphology and some infecting properties. Morphotype of φ7116 was Ackermann's A1 having an isometric head of 87-96nm diameter and a contractile tail of 200nm length. φD-86 was found to be morphotype B1, having a 67nm isometric head and a 300nm noncontractile tail. Both the phages could propagate on their each host under any pH or salt conditions in which their hosts could grow. Latent periods were both 5h and burst sizes were 27-28. Their host ranges were substantially strain-specific. They both thermally inactivated at 60°C. Stable pH ranges for φ7116 and φD-86 were 5.0-8.8 and 4.4-10.7 respectively. In diluted NaCl solutions, φD-86 was fairly stable over 0.03-2.6M but φ7116 was unstable specifically between 0.04-0.1M.