Isolation and characterisation of the bacteriocin‐producingLeuconostoc citreumHW02from malts

Abstract

Herein, a lactic acid bacterium which produces bacteriocin was isolated from malted barley. The isolated strain was identified by 16 S rRNA analysis and designated Leuconostoc citreum HW02. Bacteriocin HW02 was shown to have growth inhibition against health-threatening Gram-positive microorganisms such as Staphylococcus aureus, Listeria monocytogenes, and Latilactobacillus curvatus. Bacteriocin HW02 was reported to be incapable of inhibiting the growth of health-threatening microorganisms after treatment with proteolytic enzymes; thus, it was indicated that bacteriocin is proteinaceous in nature. Bacteriocin HW02 showed stability against a broad range of temperatures (60-121 °C), pH (2-10), various detergents, or organic solvents. Its antimicrobial activity against the indicator strain, Lactiplantibacillus plantarum NCDO 955, was maximised (320 AU mL À1 ) midway through the stationary phase at 12 h. The crude bacteriocin HW02 molecular weight was estimated to be about 7.7 kDa. After the treatment of the indicator strain with bacteriocin, the maintenance of the optical density of the culture, the morphological analysis of cell-structure abnormalities, and cell shrinkage implied that bacteriocin showed bactericidal activity.

Genomic characterization and probiotic potential of lactic acid bacteria isolated from feces of guinea pig (Cavia porcellus)

“…Molecular analyses afford heightened precision in the identification of microorganisms possessing optimal probiotic characteristics. The identification of L. citreum , characterized as Gram-positive cocci with negative catalase activity, aligns with reports highlighting its probiotic capacity to inhibit pathogenic microorganisms ( Muthusamy et al , 2023 ; Ahn et al , 2023 ). Members of this genera also have been isolated from fermented Torshi showing a high acid and bile tolerance ( Nemati et al , 2023 ).…”

Antibiofilm activity of crude bacteriocin JM01 produced by Pediococcus acidilactici against methicillin‐resistant Staphylococcus aureus (MRSA)

“…The 24‐well culture plate was incubated at 37 °C for 24 h. The dehydration step of the incubated samples was followed by the method applied by Ahn et al . (2023). The dried sample was coated with platinum (Sputter Coater 108 Auto, Cressington Scientific Instruments, Watford, UK) and viewed under a JSM‐7800F Prime Field Emission Scanning Electron Microscope (JEOL Ltd., Tokyo, Japan) at ×1000 and ×5000 magnifications.…”

“…Sterilised coverslips (SPL Life Sciences Co., Ltd) were placed in each well of a 24-well culture plate (SPL Life Sciences Co., Ltd), and bacteria were inoculated to each well in the presence or absence of JM01 bacteriocin (2.5 mg/ mL). The 24-well culture plate was incubated at 37 °C for 24 h. The dehydration step of the incubated samples was followed by the method applied by Ahn et al (2023). The dried sample was coated with platinum (Sputter Coater 108 Auto, Cressington Scientific Instruments, Watford, UK) and viewed under a JSM-7800F Prime Field Emission Scanning Electron Microscope (JEOL Ltd., Tokyo, Japan) at ×1000 and ×5000 magnifications.…”