Optimization of benzo[α]pyrene degradation by Enterococcus faecium using response surface methodology.

Area of Science:

• Environmental Microbiology
• Bioremediation
• Food Safety

Background:

• Benzo[α]pyrene (BaP) is a persistent organic pollutant (POP) with significant environmental and health concerns.
• Conventional methods for BaP removal are often inefficient or costly.
• Probiotic-based bioremediation offers a promising alternative for mitigating BaP contamination.

Purpose of the Study:

• To isolate and characterize a novel BaP-degrading probiotic from Kefir grains.
• To optimize the degradation conditions for BaP removal by the identified probiotic.
• To evaluate the potential of the probiotic for food-grade applications in BaP mitigation.

Main Methods:

• Isolation and identification of BaP-degrading bacteria from Kefir grains.
• Single-factor experiments to determine initial optimal degradation conditions.
• Response surface methodology (Box-Behnken design) to optimize pH, temperature, BaP concentration, and inoculum size.
• Analysis of Variance (ANOVA) to validate the statistical model.

Main Results:

• A novel BaP-degrading probiotic, Enterococcus faecium MA-4, was successfully isolated.
• Inoculum size was identified as the predominant factor influencing BaP degradation.
• Optimal conditions (pH 6.5, 35°C, 7 mg/L BaP, 10% inoculum) enhanced BaP degradation to 61.52%.
• A statistically significant quadratic regression model (R² = 0.9232, F=12.03) accurately predicted degradation rates.

Conclusions:

• Enterococcus faecium MA-4 demonstrates significant potential for the bioremediation of Benzo[α]pyrene.
• Optimized conditions enhance the efficiency of BaP degradation by this probiotic.
• Further safety assessments are necessary for the application of Enterococcus faecium in food, but the findings offer guidance for probiotic-based BaP remediation.