Growth, enzymatic production and morphology of the white-rot fungi Lentinus crinitus (L.) Fr. upon 2,4-D herbicide exposition

摘要

Dichlorophenoxyacetic acid (2,4-D) is one of the most commonly used weed control herbicides. White-rot fungi (WRF) are recognized as a degrader of a wide range of molecules because due to their enzymatic plasticity, nevertheless, the knowledge of their ability to degrade 2,4 D residues in the environment is still limited. In this study, the tolerance and the mycelium growth kinetics of twelve WRF to 2,4-D (670 g L-1) were evaluated on potato dextrose agar added with 2,4-D using the technique of cup plate. Agaricus sp., Pleurotus pulmonarius, Pleurotus djamor and the EF 58 strain grew in all plates in the presence of 2,4-D. Molecular phylogenetic analysis of the EF 58 strain allowed its determination as a lineage belonging to Lentinus crinitus Fr. (Polyporales, Basidiomycota) species-complex. The daily fungal growth rate of L. crinitus EF 58 lineage in medium with (5.025 g L-1 and 50.25 g L-1) and without the addition of the herbicide, laccase production and mycelium structure after 6, 10 and 15 days of exposure to 2,4-D was analyzed. There were no significant differences between the control and C1 treatments concerning the growth of L. crinitus EF 58 lineage. The enzymatic activity tests showed evidence for the presence of laccases in all essays. Optical microscopy observations did not reveal substantial alterations in its mycelium morphology after exposition to the herbicide. It was the first study showing the potential of L. crinitus EF58 lineage in tolerating 2,4-D what represents the beginning of work for the bioremediation process with practical applications.