Bioprospecção de fungos de interesse biotecnológico na degradação dos herbicidas 2,4-D e Imazapyr [marca registrada]

Abstract

Environmental pollution has increased due to the uncontrolled addition of chemical substances in the soil, among these herbicides can be highlighted. The application of herbicides in agricultural crops has been a practice for years and this activity, besides causing environmental problems such as contamination of water, soil and air can also cause damage to human and animal health and is associated with some diseases due to toxicity of these compounds. This work aimed to isolate microbial strains with degrading activity of the herbicides 2,4- dichlorophenoxyacetic acid (2,4-D) and 2-4,5-dihydro-4-methyl-4-1-methylethyl-5-oxo-1Himidazol-2-yl-3-pyridinecarboxylic acid (Imazapyr [marca registrada]) from a soil sample collected from an area with a history of application of pesticides. Two fungal isolates were obtained and characterized macromorphologically and micromorphologically and finally identified by molecular biology. The isolates were evaluated for herbicide growth, herbicide production and herbicide degradation by isolates. The fungi were identified as Fusarium oxysporum (2,4-D isolate) and Fusarium solani (isolated from Imazapyr [marca registrada]). A third strain, a yeast, was isolated from a petri dish containing the herbicide Imazapyr [marca registrada] as the carbon source. The herbicides did not affect mycelial growth and morphological characteristics, however, altered amylase, protease and cellulase production in F. solani and increased esterase synthesis in F. oxysporum. There was a reduction in the number of macroconides in the fungus F. oxysporum in the presence of 2,4-D. High performance liquid chromatographyshowed that the fungus F. oxysporum was able to reduce the concentration of 2,4-D in 11 and 18% when grown in MSM and Czapeck-Dox medium respectively, suggesting that the culture medium interferes with the process of degradation. L-1 yeast induced a peak elevation in the chromatogram of both herbicides suggesting that this isolate may be promoting modifications in these substances. F. oxysporum isolates and L-1 yeast may be promising herbicide degrading agents.