Factors Affecting Aflatoxin B₁ Removal by Flavobacterium aurantiacum

Area of Science:

• Microbiology
• Food Safety
• Bioremediation

Background:

• Aflatoxin B1 is a potent mycotoxin posing significant health risks.
• Effective methods for aflatoxin B1 removal are crucial for food safety and public health.
• Flavobacterium aurantiacum has shown potential for mycotoxin degradation.

Purpose of the Study:

• To investigate factors influencing aflatoxin B1 removal by Flavobacterium aurantiacum NRRL B-184.
• To compare a spectrophotometric method with high-performance liquid chromatography (HPLC) for aflatoxin quantification.
• To determine optimal conditions for aflatoxin B1 bioremediation using F. aurantiacum.

Main Methods:

• A spectrophotometric assay was developed and validated against HPLC for aflatoxin B1 measurement.
• The influence of bacterial culture age (24-h vs. 72-h) on aflatoxin removal was assessed.
• The effect of cell population density (10^9 vs. 10^10 cells) on aflatoxin removal rate was evaluated.
• The long-term stability of F. aurantiacum's aflatoxin removal capability was tested over 8 months.
• The role of viable bacterial cells in aflatoxin B1 removal was examined using heat-inactivated F. aurantiacum.

Main Results:

• The spectrophotometric method proved reliable for determining aflatoxin concentration.
• 72-hour-old F. aurantiacum cultures demonstrated superior aflatoxin B1 removal compared to 24-hour-old cultures.
• Higher cell densities (10^10 cells) resulted in faster aflatoxin removal rates than lower densities (10^9 cells).
• Consistent toxin removal was observed over an 8-month period with regular subculturing.
• Heat-inactivated F. aurantiacum populations (≤ 1 × 10^9 CFU/ml) did not remove aflatoxin B1.

Conclusions:

• Flavobacterium aurantiacum is an effective agent for aflatoxin B1 bioremediation.
• Culture age and cell density are critical factors influencing the rate of aflatoxin B1 removal.
• Viability of F. aurantiacum cells is essential for successful aflatoxin B1 detoxification.
• The study validates a simple spectrophotometric method for monitoring aflatoxin B1 reduction.