Isolation and characterization of bacteriocin-producing Pediococcus acidilactici HW01 from malt and its potential to control beer spoilage lactic acid bacteria

A bacteriocin-producing lactic acid bacterium was isolated from malts. The isolate was identified as Pediococcus acidilactici by morphological, API 50 CHL kit and 16S rRNA analysis, and designated as strain HW01. The antimicrobial activity was maintained over a broad pH range (pH2-11). Proteolytic enzymes and alpha-amylase treatments inactivated the bacteriocin activity; while catalase, heat, detergents, and solvents did not. The molecular weight of the crude bacteriocin was approximately 6 kDa by SDS-PAGE. The bacteriocin production phenotype (Bac(+)) was linked to a 9.8 kb plasmid and was not increased by co-culture with an indicator microorganism. Bacteriocin HW01 inhibited several Gram-positive bacteria, including health-threatening microorganisms (Staphylococcus aureus, Streptococcus mutans, Lactobacillus curvatus, Listeria monocytogenes, and L. innocua). Particularly, Pediococcus damnosus and P. claussenii, which were isolated from spoiled beer, were strongly antagonised by the bacteriocin. P. acidilactici HW01 has tolerance to hop compounds but is unable to grow in a simulated beer environment. The potential of the HW01 strain, as a starter culture in brewing, to control beer spoilage lactic acid bacteria, is discussed. (C) 2017 Elsevier Ltd. All rights reserved.