RIBOSOMAL AND NUCLEAR PROTEINS WITH ANTIBACTERIAL ACTIVITY, RECOVERED FROM THE ACIDIFIED EXTRACTS OF ISOLATED LACTOBACILLUS SAKEI SUBSP. SAKEI 2A CELLS

JACQUES NICOLI; ALEXANDRE SANTOS; FELIPE HENRIQUE DA SILVA BAMBIRRA; MARCELO PORTO BEMQUERER; BERNADETTE DORA GOMBOSSY DE MELO FRANCO; KATIA GIANNI DE CARVALHO; JAMIL OLIVEIRA; ANTONIO DE MIRANDA

San Miguel de Tucuman

Simposio; V International Symposium on Lactic Acid Bacteria; 2016

CERELA

Bacteriocins and other antimicrobial compounds produced by lactic acid bacteria are gaining increased importance due to their possible use as biopreservatives in foods . L. sakei subsp. sakei 2a, isolated from a Brazilian meat product, has reported that this strain produces sakacin P and several other ribosomal proteins with antibacterial activity, capable of affecting the membrane electrochemical potential of Listeria monocytogenes. The aims were to purify and characterize the multiple antimicrobial compounds produced by L. sakei subsp. sakei 2a, and to test their effectiveness for the control of Listeria monocytogenes in simulated meat gravy.In the present study, a concentrated acid extract of a culture of Lactobacillus sakei subsp. sakei 2a, was purified by cation exchange and reversed-phase chromatographic methods and the amino acid sequences of the active antimicrobial compounds were determined by Edman degradation. The antimicrobial compounds purified by HLPC and sequencing by Edman degradation corresponded to sakacin A, a histone-like DNA-binding protein HV, a transcription factor IF-1 and six other proteins, and all of them with antilisterial activity and capable to increase efflux of ATP and decrease ∆Ψ in L. monocytogenes . When tested in the meat gravy model, both the L. sakei subsp. sakei 2a culture and acid extract containing antilisterial compounds added to the product inhibited growth of L. monocytogenes Scott A. The inoculated gravy portions were maintained at 4oC for ten days, and counts of L. monocytogenes Scott A and L. sakei subsp. sakei 2a were performed at times zero, five and ten days. In the control experiment, counts of L. monocytogenes Scott A in the gravy stored at 4oC reached 5.0 log CFU/mL after five days and remained the same until ten days. In the gravy containing the bacteriogenic strain or the acid extract, the growth of L. monocytogenes Scott A was inhibited to an extent that the population of the pathogen in the product stored at 4oC for five days was 0.6 to 1 log lower than the initial population (103 CFU/mL).The results obtained indicate that L. sakei subsp. sakei 2a is capable to produce several antimicrobial compounds with different mechanism of action and that the acid extract or a culture of this strain has a potential for application in processed food to inhibit the growth of L. monocytogenes.