Atrazine degradation by fungal co-culture enzyme extracts under different soil conditions

ABSTRACT

This investigation was undertaken to determine the atrazine degradation by fungal enzyme extracts (FEEs) in a clay-loam soil microcosm contaminated at field application rate (5 μg g⁻¹) and to study the influence of different soil microcosm conditions, including the effect of soil sterilization, water holding capacity, soil pH and type of FEEs used in atrazine degradation through a 2⁴ factorial experimental design. The Trametes maxima–Paecilomyces carneus co-culture extract contained more laccase activity and hydrogen peroxide (H₂O₂) content (laccase = 18956.0 U mg protein⁻¹, H₂O₂ = 6.2 mg L⁻¹) than the T. maxima monoculture extract (laccase = 12866.7 U mg protein⁻¹, H₂O₂ = 4.0 mg L⁻¹). Both extracts were able to degrade atrazine at 100%; however, the T. maxima monoculture extract (0.32 h) achieved a lower half-degradation time than its co-culture with P. carneus (1.2 h). The FEE type (p = 0.03) and soil pH (p = 0.01) significantly affected atrazine degradation. The best degradation rate was achieved by the T. maxima monoculture extract in an acid soil (pH = 4.86). This study demonstrated that both the monoculture extracts of the native strain T. maxima and its co-culture with P. carneus can efficiently and quickly degrade atrazine in clay-loam soils.

Keywords:

• Fungal interaction
• herbicide
• ligninolytic enzymes
• mycoremediation
• soil sterilization
• water holding capacity

Acknowledgments

The first author would like to thank to National Council of Science and Technology (CONACyT) for its doctoral fellowship, which allowed his studies in The Institute of Ecology (INECOL A. C.).