Bacteriocin-like inhibitory substances (BLIS) produced by Bacillus cereus: Preliminary characterization and application of partially purified extract containing BUS for inhibiting Listeria monocytogenes in pineapple pulp

摘要

The application of conventional preservatives in food has been reassessed due to the toxicity of some of classical additives, and it is important to search for new food preservation strategies. Thus, this study aimed to characterize an antilisterial bacteriocin-like inhibitory substances (BUS) produced by Bacillus cereus LFB-FIOCRUZ 1640 and to evaluate the potential of the BUS in pineapple pulp biopreservation. The proteinaceous nature of BUS was confirmed by susceptibility to the enzyme alpha-chymotrypsin and it showed thermal stability for up to 30 min at 80 degrees C and in a wide pH range. After partial purification of the BLIS with Amberllite XAD-16 resin and cation-exchange SP-Sepharose "Fast Flow", it was obtained a purification factor of 4.1 times and 30% of yield, and SDS-PAGE analyses revealed that the peptide has approximately 24.8 kDa. The Minimum Bactericidal Concentration (MBC) of 2 mg mL(-1) was determined with the biological indicator Listeria monocytogenes and this concentration of BLIS was applied in a model system containing pineapple pulp. The BUS was bactericidal towards L. monocytogenes after 24 h at 37 degrees C, and these results indicate the application of the BUS produced by B. cereus LFB-FIOCRUZ 1640 in food, especially for fruit pulp biopreservation. (C) 2016 Elsevier Ltd. All rights reserved.