Substrate regulation on co-metabolic degradation of β-cypermethrin by Bacillus licheniformis B-1

Beta-cypermethrin (β-CY) residues are a serious threat to food safety and human health. However, the residues are not efficiently biodegraded because microorganisms preferentially use the nutrients found in food and the environment for growth. In this study, the mechanisms underlying nutrient regulation during co-metabolic degradation of β-CY by Bacillus licheniformis B-1 were investigated. The strain B-1 resting cells and the suspension containing NaN₃ showed no significant differences in β-CY degradation. The co-metabolic degradation and strain B-1 growth could be separately inhibited by iodoacetic acid and sodium fluoride. Adenosine monophosphate (AMP), fructose 1-6 bisphosphate (F1-6BP), Mg²⁺, and Mn²⁺ could improve the degradation, whereas adenosine triphosphate (ATP), alanine (Ala), phenylalanine (Phe), and phosphoenolpyruvate (PEP) were found to exert the opposite effect, indicating that β-CY degradation was positively associated with pyruvate kinase activity. Furthermore, glycerol, urea, ammonium chloride and peptone improved β-CY degradation in corn flour. The results provided a promising approach for nutrient regulation of pyrethroids biodegradation in food and the environment.