Kombucha fermentation and its antimicrobial activity

Area of Science:

• Microbiology
• Food Science
• Biotechnology

Background:

• Kombucha is a fermented tea beverage with reported health benefits.
• Its antimicrobial properties are often attributed to acetic acid.
• The fermentation process involves yeasts and acetic acid-producing bacteria.

Purpose of the Study:

• To characterize the fermentation process of Kombucha.
• To evaluate the antimicrobial activity of Kombucha against various pathogenic microorganisms.
• To investigate the nature of the antimicrobial compounds present in Kombucha.

Main Methods:

• Kombucha preparation using tea broth, sucrose, and a starter culture.
• Monitoring of pH, microbial counts (yeasts and acetic acid bacteria), and optical density during fermentation.
• Antimicrobial activity testing against a panel of pathogenic bacteria.
• Assessment of antimicrobial activity under different conditions (neutral pH, thermal denaturation).

Main Results:

• Kombucha fermentation led to a significant pH decrease and increased microbial populations.
• Kombucha demonstrated broad-spectrum antimicrobial activity against tested pathogens.
• Antimicrobial activity was observed even at neutral pH and after thermal denaturation, suggesting non-acetic acid, non-protein compounds are involved.

Conclusions:

• Kombucha fermentation is characterized by specific physicochemical and microbial changes.
• Kombucha possesses significant antimicrobial properties against a wide range of pathogens.
• The findings indicate the presence of novel antimicrobial agents in Kombucha beyond acetic acid and large proteins.