Isolation and lytic activity of the Listeria bacteriophage endolysin LysZ5 against Listeria monocytogenes in soya milk

The endolysin gene (lysZ5) from the genome of the Listeria monocytogenes phage FWLLm3 was cloned in Escherichia coli and characterized. Comparative sequence analysis revealed that lysZ5 resembled the murein hydrolase ply511 encoded by L. monocytogenes phage A511. The encoded protein LysZ5 had a pred...

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Bibliographic Details
Published inFood microbiology Vol. 31; no. 1; pp. 133 - 136
Main Authors Zhang, Hui, Bao, Hongduo, Billington, Craig, Hudson, J. Andrew, Wang, Ran
Format Journal Article
LanguageEnglish
Published Kidlington Elsevier Ltd 01.08.2012
Elsevier
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Summary:The endolysin gene (lysZ5) from the genome of the Listeria monocytogenes phage FWLLm3 was cloned in Escherichia coli and characterized. Comparative sequence analysis revealed that lysZ5 resembled the murein hydrolase ply511 encoded by L. monocytogenes phage A511. The encoded protein LysZ5 had a predicted molecular mass of 35.8 kDa and was expressed in E. coli as an N-terminal fusion protein of 41.5 kDa. Addition of purified fusion protein to lawns of indicator bacteria showed that LysZ5 could lyse L. monocytogenes, Listeria innocua and Listeria welshimeri, but not Staphylococcus aureus or Enterococcus faecalis. The purified protein was able to kill L. monocytogenes growing in soya milk, with the pathogen concentration reduced by more than 4 log10 CFU ml−1 after 3 h incubation at 4 °C. As far as we know, this is the first report of a Listeria phage endolysin to control pathogens in soya milk and to demonstrate endolysin activity in foods at refrigeration temperatures. Moreover, LysZ5 may also be useful for biocontrol in other ready-to-eat foods. ► A newly identified phage endolysin rapidly lysed Listeria monocytogenes in broth at 25 °C. ► The endolysin was active against L. monocytogenes in soya milk and control was achieved under refrigeration. ► This is the first report of a cloned phage endolysin active at temperatures used for the chilled storage of foods.
ISSN:0740-0020
1095-9998
DOI:10.1016/j.fm.2012.01.005