Screening of Bacteriocin Production from Moderately Halophilic Skin Isolates to Inhibit Moderately Halophilic Bacteria Producing Protease and Lipase

Abstract

Bacteriocins, produced from a wide variety of microorganisms toinhibit or kill different species of bacteria, have received increasedattention in different industries. Hence, bacteriocins produced frommoderately halophilic skin isolates were examined to demonstratetheir inhibitory effect against enzyme-producing (protease orlipase) skin isolates. Eleven identified skin isolates, obtained fromsalted goat and sheep skins, were used as test isolates. Ten of theseisolates (Halomonas halodenitrificans, Halomonas halmophila,Salimicrobium salexigens, Gracilibacillus dipsosauri, Salinivibriocosticola subsp. alkaliphilus, Halomonas venusta, Planococcusrifietoensis, Marinococcus tarijensis, Halomonas eurihalina,Staphylococcus arlettae) showed antimicrobial effect against eachother. Although Halomonas halodenitrificans, Salimicrobiumsalexigens, Halomonas venusta did not produce enzyme, the otherisolates produced protease or lipase enzymes. While bacteriocinproduced from Halomonas halodenitrificans was found to beeffective against enzyme-producing Gracilibacillus dipsosauri,Planococcus rifietoensis and Halomonas eurihalina, bacteriocin ofSalimicrobium salexigens was effective against enzyme-producingSalinivibrio costicola subsp. alkaliphilus, Marinococcus tarijensisand Halomonas eurihalina. Bacteriocin of Halomonas venusta waseffective against enzyme-producing Halomonas halmophila,arinococcus tarijensis, Halomonas eurihalina, Idiomarinaloihiensis and Staphylococcus arlettae. The maximum bacteriocinproduction of these skin isolates was obtained at 37°C, pH 7.0, and10% salt concentration. Antimicrobial activities of the bacteriocinsagainst all test isolates were detected at 10°C-60°C, pH 6.0-8.0 and3%-20% salt concentrations. Antimicrobial activities of allbacteriocins against test isolates were not detected after thetreatment with proteinase K. Minimal inhibitory concentration(MIC) values of the bacteriocins against the test isolates weredetected as 1/2, 1/4 or 1/8. Scanning electron micrographs ofsheepskins showed that sterile bacteriocins of Halomonashalodenitrificans, Salimicrobium salexigens, Halomonas venustamay be used in leather industry to prevent the growth of proteaseand lipase producing moderately halophilic bacteria.