Insights into the microbial degradation pathways of the ioxynil octanoate herbicide

Autor(es)

Oliveira, Karina O. ^[1] ; Silva, Amanda R. M. ^[2] ; da Silva, Bianca F. ^[1] ; Milagre, Humberto M. S. ^[1] ; Milagre, Cintia D. F. ^[1]

Afiliação do(s) autor(es)

^[1] UNESP Sao Paulo State Univ, Inst Chem, BR-14800060 Araraquara, SP - Brazil

^[2] Univ Sao Paulo, Inst Chem, BR-05508000 Sao Paulo, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: BIOCATALYSIS AND AGRICULTURAL BIOTECHNOLOGY; v. 13, p. 258-264, JAN 2018.
• Citações Web of Science: 2

Resumo

This paper describes the biodegradation of the ioxynil octanoate herbicide by indigenous microorganisms isolated from herbicide impacted soil-enrichment cultures. Eleven positive hits out of twenty-nine microorganisms screened for nitrile hydratase, nitrilase and amidase activity were further evaluated based on their growth in microtiter plates containing liquid medium with increasing concentrations of herbicide (0.97-250 mM). Two strains were selected from this assay for biodegradation studies and were identified as Lysinibacillus boronitolerans MLH-31 and Bacillus cereus MLH-61. The bacterial degradation of ioxynil octanoate and its biodegradation products were monitored, identified and characterized by liquid chromatography tandem mass spectrometry (HPLC-MS/MS). In addition to 3,5-diiodo-4-hydroxybenzamide and 3,5-diiodo-4-hydroxybenzoic acid, which are commonly detected metabolites, two new metabolites were observed: mono-deiodinated compound 3-iodo-4-hydroxybenzoic acid and the product of Caromatic-CN cleaved 1,3-diiodophenol. The experimentally observed metabolites were correlated with the enzymatic systems involved, revealing the presence of esterases, nitrile hydratases, amidases, nitrilases, dehalogenases and carbon-carbon lyases during biodegradation. Lysinibacillus boronitolerans MLH-31 was found to degrade ioxynil octanoate at a rate of 97% over 7 days through a batch-resting cells experiment, while Bacillus cereus MLH-61 was found to do so at a rate of 75% under the same conditions. (AU)

• Processo FAPESP: 10/02305-5 - Transformações microbianas de nitrilas: prospecção de micro-organismos, síntese de compostos quirais bioativos e biodegradação
• Beneficiário: Cintia Duarte de Freitas Milagre
• Modalidade de apoio: Auxílio à Pesquisa - Jovens Pesquisadores
• Processo FAPESP: 14/50249-8 - Green chemistry: sustainable synthetic methods employing benign solvents, safer reagents, and bio-renewable feedstock
• Beneficiário: Arlene Gonçalves Corrêa
• Modalidade de apoio: Auxílio à Pesquisa - Programa Centros de Pesquisa em Engenharia