Enzymatic activity, osmotic stress and degradation of pesticide mixtures in soil extract liquid broth inoculated with Phanerochaete chrysosporium and Trametes versicolor.

In this study we examined the extracellular enzymatic activity of two white rot fungi (Phanerochaete chrysosporium and Trametes versicolor) in a soil extract broth in relation to differential degradation of a mixture of different concentrations (0-30 p.p.m.) of simazine, dieldrin and trifluralin under different osmotic stress (-0.7 and -2.8 MPa) and quantified enzyme production, relevant to P and N release (phosphomonoesterase, protease), carbon cycling (beta-glucosidase, cellulase) and laccase activity, involved in lignin degradation. Our results suggest that T. versicolor and P. chrysosporium have the ability to degrade different groups of pesticides, supported by the capacity for expression of a range of extracellular enzymes at both -0.7 and -2.8 MPa water potential. Phanerochaete chrysosporium was able to degrade this mixture of pesticides independently of laccase activity. In soil extract, T. versicolor was able to produce the same range of enzymes as P. chrysoporium plus laccase, even in the presence of 30 p.p.m. of the pesticide mixture. Complete degradation of dieldrin and trifluralin was observed, while about 80% of the simazine was degraded regardless of osmotic stress treatment in a nutritionally poor soil extract broth. The capacity of tolerance and degradation of high concentrations of mixtures of pesticides and production of a range of enzymes, even under osmotic stress, suggest potential bioremediation applications.