Multi-Approach Characterization of Novel Pyrene-Degrading Mycolicibacterium austroafricanum Isolates Lacking nid Genes

• Published in: Microorganisms (Basel) Vol. 11; no. 6; p. 1413
• Main Authors: Silva, Natalia Maria, Romagnoli, Camila Lopes, Santiago, Caio Rafael do Nascimento, de Lacerda, João Paulo Amorim, Leão, Sylvia Cardoso, Digiampietri, Luciano Antonio, Viana-Niero, Cristina
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 27-05-2023; MDPI
• Subjects: 2,6-Dichlorophenol; Bacteria; Biodegradation; Carcinogens; Chemical compounds; Cytochrome P450; Cytochromes P450; Degradation; Dioxygenase; Gas chromatography; gas chromatography/mass spectrometry; Genes; Genomic analysis; Genomic islands; Genomics; Industrial wastes; Mass spectrometry; Mass spectroscopy; Microbial degradation; Microorganisms; Molecular weight; Parks & recreation areas; Petrochemicals; polycyclic aromatic hydrocarbon; Polycyclic aromatic hydrocarbons; Pyrene; Service stations; Brazil; United States > US; gas chromatography/mass spectrometry; genomic analysis; polycyclic aromatic hydrocarbon
• ISSN: 2076-2607; 2076-2607
• DOI: 10.3390/microorganisms11061413

Polycyclic aromatic hydrocarbons (PAHs) are chemical compounds that are widespread in the environment, arising from the incomplete combustion of organic material, as well as from human activities involving petrol exploitation, petrochemical industrial waste, gas stations, and environmental disasters. PAHs of high molecular weight, such as pyrene, have carcinogenic and mutagenic effects and are considered pollutants. The microbial degradation of PAHs occurs through the action of multiple dioxygenase genes (
), which are localized in genomic island denominate region A, and cytochrome P450 monooxygenases genes (
) dispersed in the bacterial genome. This study evaluated pyrene degradation by five isolates of
using 2,6-dichlorophenol indophenol (DCPIP assay), gas chromatography/mass spectrometry (CG/MS), and genomic analyses. Two isolates (MYC038 and MYC040) exhibited pyrene degradation indexes of 96% and 88%, respectively, over a seven-day incubation period. Interestingly, the genomic analyses showed that the isolates do not have
genes, which are involved in PAH biodegradation, despite their ability to degrade pyrene, suggesting that degradation may occur due to the presence of
150 genes, or even genes that have not yet been described. To the best of our knowledge, this is the first report of isolates without
genes demonstrating the ability to degrade pyrene.