Related Experiment Video
Updated: Jul 29, 2026
06:05
Using the Overlay Assay to Qualitatively Measure Bacterial Production of and Sensitivity to Pneumococcal Bacteriocins
Published on: September 30, 2014
Pediocin production by recombinant lactic acid bacteria
1Eastern Regional Research Center, Agricultural Research Service, U.S. Department of Agriculture, 600 East Mermaid Lane, Wyndmoor, PA 19038, USA. gsomkuti@arserrc.gov
Biotechnology Letters
|July 29, 2003
Summary
Optimizing pediocin production by lactic acid bacteria (LAB) involves specific media and temperatures. Recombinant LAB strains effectively produce pediocin in skim milk and cheese whey, offering cost-effective antimicrobial solutions.
Area of Science:
- Microbiology
- Food Science
- Biotechnology
Background:
- Lactic acid bacteria (LAB) produce bacteriocins like pediocin, which exhibit antimicrobial properties against pathogens such as Listeria.
- Genetic engineering of LAB strains can enhance pediocin production for food preservation applications.
Purpose of the Study:
- To investigate the influence of media composition and incubation temperature on pediocin production by transformed LAB.
- To evaluate the efficacy of different growth media, including dairy byproducts, for pediocin synthesis.
Main Methods:
- LAB strains (Lactococcus lactis, Streptococcus thermophilus, Enterococcus faecalis) were transformed with the pPC418 vector for enhanced pediocin production.
- Pediocin production was quantified under various conditions, including different media (tryptone/lactose/yeast extract, skim milk, cheese whey) and temperatures (30°C, 40°C).
- The impact of media dilution on pediocin yield was assessed.
Main Results:
- Optimal pediocin production by Lactococcus lactis transformants occurred at 30°C in tryptone/lactose/yeast extract medium.
- Streptococcus thermophilus and Enterococcus faecalis transformants showed maximum pediocin yield at 40°C.
- Streptococcus thermophilus produced significant amounts of pediocin in skim milk (51,000 units/mL) and cheese whey (25,000 units/mL) with minimal yeast extract supplementation.
- Pediocin production levels were stable in reconstituted skim milk and whey media diluted up to 10-fold.
Conclusions:
- Media composition and incubation temperature are critical factors for optimizing pediocin production by recombinant LAB.
- Recombinant LAB strains demonstrate the potential for producing pediocin in cost-effective and readily available media like skim milk and cheese whey.
- These findings support the development of pediocin as a natural antimicrobial agent for food safety applications.
Related Concept Videos
01:29Microbes in Food Production
Microbial fermentation is central to food biotechnology, enhancing flavor, texture, preservation, and stability. Fermentative microorganisms metabolize carbohydrates into organic acids, alcohols, and other metabolites that inhibit spoilage organisms and improve digestibility while contributing distinctive sensory qualities.In baking, amylases naturally present in flour hydrolyze starch into monosaccharides such as glucose, which Saccharomyces cerevisiae ferments anaerobically. Through...
01:27Microbes in the Production of Fermented Foods
Lactic acid bacteria (LAB) and molds are instrumental in fermenting plant-based foods to enhance preservation and ensure year-round availability. These microbial processes convert plant carbohydrates into organic acids and other metabolites that inhibit spoilage organisms and contribute to the sensory qualities of the final product.In sauerkraut production, cabbage goes through a microbial succession that starts with cocci such as Leuconostoc mesenteroides. These microbes begin fermentation by...
01:22Probiotics
Probiotics are live, non-pathogenic microorganisms that confer health benefits by modulating the gut microbiota. The human gastrointestinal tract harbors a complex microbial ecosystem, and the balance of this microbiota is crucial for digestive and systemic health. Among the most extensively studied and utilized probiotics are species formerly classified within the genera Lactobacillus and Bifidobacterium. These organisms not only naturally colonize the human gut but are also consumed through...
01:25Production of Organic Acids
Lactic acid, an important organic acid extensively applied in food, pharmaceutical, and biodegradable polymer industries, is primarily produced via microbial fermentation. This method is favored over chemical synthesis due to its environmental sustainability and capacity for enantiomerically pure product formation. Among various microbial processes, the fermentation of starch-based substrates stands out due to the abundance and renewability of raw materials like corn and potatoes.Hydrolysis of...
01:27Production of Antibiotics
Penicillin, one of the earliest and most widely used antibiotics, is produced industrially by the filamentous fungus Penicillium chrysogenum. Large stirred-tank bioreactors ranging from tens to hundreds of thousands of liters maintain tightly controlled temperature, pH, and dissolved oxygen conditions to support fungal metabolism and maximize antibiotic yield. Penicillin is a secondary metabolite, synthesized primarily during the stationary growth phase, which requires a carefully managed...
01:30Production of Pharmaceuticals
Industrial insulin production uses genetically engineered E. coli expressing a proinsulin gene controlled by a tryptophan promoter and containing a methionine linker for later cleavage. The cells also carry ampicillin resistance for selective growth. Seed cultures are stored at −80 °C and production begins by thawing a small amount to inoculate starter cultures, which are progressively scaled to a 50,000-L bioreactor. In the bioreactor, E. coli grow in nutrient-rich media under sterile, tightly...