Characterization of the Extremely Heat-Stable Antibacterial Activity Produced by a Newly Selected Local Bacillus Probiotic Strain

Bacterial food poisoning and food spoilage cause significant economic losses and pose serious public health concerns. Although chemical preservatives can inhibit or kill foodborne pathogens, many have been banned due to safety concerns, increasing the need for natural, safe alternatives. Bacteriocins, ribosomally synthesized peptides with antibacterial activity, are one such promising options. Produced by several bacteria, including Bacillus species, bacteriocins have demonstrated broad-spectrum antimicrobial activity and potential application in food preservation. Bacillus amyloliquefaciens, known for its probiotic potential and production of antimicrobial substances, has attracted attention for its prebiotic, probiotic, and functional food applications. This study aimed to determine the optimal conditions for bacteriocin production and characterize the bacteriocin-like antibacterial compound produced by the newly selected extremophile probiotic strain Bacillus amyloliquefaciens 37. The optimal bacteriocin production conditions were investigated by evaluating the impact of preculture medium, culture medium, flask volume, and incubation time. The antibacterial compound’s nature and stability were tested using enzymatic, heat, and pH treatments. The antimicrobial spectrum was assessed against multiple foodborne pathogens, and the mode of action was determined using Staphylococcus aureus as an indicator strain.