Bacteriocin research and commercial applications

The second blog article from Yi Xu, completed during his winter industry experience internship placement with us from July 22 to August 16. Each article develops ideas about bacteriocins and extends our understanding of them.

In the world of food safety, ensuring that our food is free from harmful bacteria is a top priority. One of the most promising tools in this fight is bacteriocins. These are antimicrobial peptides produced by bacteria that can kill or inhibit the growth of other bacteria. Let’s dive into the fascinating world of bacteriocins and explore their classification, global trends, and how food manufacturers can incorporate them into their processes.

Classification of bacteriocins

Bacteriocins are classified based on the type of bacteria that produce them and their structural characteristics. Here’s a simplified breakdown:

1. Bacteriocins from Gram-positive bacteria (GPB)
   • Class I (Lantibiotics): These are small peptides (<5 kDa) that undergo post-translational modifications, which means they are chemically altered after being made. They contain unusual amino acids and are known for their stability and effectiveness against food-borne pathogens.
   • Class II (Non-Lantibiotics): These are also small peptides (<10 kDa) but with limited post-translational modifications. They are heat-stable and can form pores in bacterial membranes, leading to cell death.
   • Class III: These are larger peptides (>30 kDa) that are heat-labile, meaning they lose their activity when heated. They can either lyse (break down) bacterial cells or inhibit their growth without lysing them.
   • Class IV: These contain lipid or carbohydrate parts, making them unique in structure. They disrupt bacterial cell membranes and are sensitive to enzymes that break down fats and sugars.
2. Bacteriocins from Gram-negative bacteria (GNB)
   • Colicins: Produced by Escherichia coli, these bacteriocins are large (>10 kDa) and can either form pores in bacterial cell walls or degrade nucleic acids.
   • Colicin-like Bacteriocins: Similar to colicins but produced by other bacteria like Klebsiella and Pseudomonas.
   • Microcins: These are smaller peptides (<10 kDa) and can be further divided into those that are post-translationally modified and those that are not. They target various cellular processes, including membrane disruption and enzyme inhibition.
   • Phage Tail-Like Bacteriocins: These resemble the tail structures of bacteriophages (viruses that infect bacteria) and can form pores in bacterial membranes, leading to cell death.

Global trends in bacteriocin research

The interest in bacteriocins has been growing globally due to their potential as natural preservatives in the food industry and as alternatives to traditional antibiotics. Here are some key trends:

• Increased research and development: Scientists are actively exploring new bacteriocins and their potential applications. This includes studying their mechanisms of action, improving their stability, and finding ways to produce them more efficiently.
• Applications in food safety: Bacteriocins are being incorporated into food packaging and preservation methods to extend shelf life and prevent the growth of harmful bacteria. For example, nisin, a well-known lantibiotic, is already used as a food preservative.
• Combating antibiotic resistance: With the rise of antibiotic-resistant bacteria, bacteriocins offer a promising alternative. They can be used alone or in combination with traditional antibiotics to enhance their effectiveness.
• Biotechnological advances: Advances in genetic engineering and biotechnology are enabling the production of bacteriocins with enhanced properties, such as increased potency and broader spectrum of activity.

How food manufacturers can incorporate bacteriocins

Incorporating bacteriocins into food manufacturing processes can significantly enhance food safety and extend shelf life. Here are some practical ways food manufacturers can integrate these antimicrobial peptides:

• Direct addition to food products: Bacteriocins can be directly added to food products during processing. This method is straightforward and ensures that the bacteriocins are evenly distributed throughout the product. For example, nisin, a well-known bacteriocin, is commonly added to dairy products, canned foods, and meat products to inhibit the growth of spoilage and pathogenic bacteria.
• Incorporation into packaging materials: Embedding bacteriocins into food packaging materials is an innovative approach that provides continuous protection against bacterial contamination. These antimicrobial packaging materials can release bacteriocins gradually, maintaining their effectiveness over the product’s shelf life. This method is particularly useful for perishable items like fresh produce, meats, and dairy products.
• Surface treatment: Applying bacteriocins as a surface treatment on food products can help prevent contamination during storage and handling. This method is often used for ready-to-eat foods, fruits, and vegetables. The bacteriocins can be sprayed or coated onto the surface, creating a protective barrier against harmful bacteria.
• Fermentation processes: Using bacteriocin-producing starter cultures in fermentation processes is another effective strategy. These cultures can produce bacteriocins naturally during fermentation, enhancing the safety and quality of fermented foods like yogurt, cheese, and sausages. This method leverages the natural production of bacteriocins by beneficial bacteria.
• Combination with other preservatives: Bacteriocins can be used in combination with other preservatives to create a synergistic effect, enhancing overall antimicrobial activity. This approach can reduce the required concentration of each preservative, minimising potential negative impacts on taste and texture while ensuring food safety.
• Biotechnological advances: Advances in biotechnology allow for the genetic modification of bacteria to produce bacteriocins more efficiently. Food manufacturers can use these genetically engineered bacteria in their processes to ensure a consistent and high yield of bacteriocins. This method can be particularly useful for large-scale production.
• Regulatory compliance and safety: Before incorporating bacteriocins into their processes, food manufacturers must ensure compliance with regulatory standards and safety guidelines. This includes conducting thorough safety assessments and obtaining necessary approvals from food safety authorities. Ensuring that bacteriocins are used within the approved limits is crucial for consumer safety.

Conclusion

Bacteriocins represent a powerful tool in the fight against harmful bacteria, both in food safety and in medical applications. By understanding their classification, staying informed about global trends, and incorporating them into their processes, food manufacturers can leverage these natural peptides to ensure safer and longer-lasting food products. As research continues to advance, the potential applications of bacteriocins will only expand, offering new solutions to age-old problems in food safety and beyond.