Cupriavidus metallidurans CH34 Possesses Aromatic Catabolic Versatility and Degrades Benzene in the Presence of Mercury and Cadmium

• Published in: Microorganisms (Basel) Vol. 10; no. 2; p. 484
• Main Authors: Alviz-Gazitua, Pablo, Durán, Roberto E, Millacura, Felipe A, Cárdenas, Franco, Rojas, Luis A, Seeger, Michael
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 21.02.2022; MDPI
• Subjects: aromatic catabolism; Aromatic hydrocarbons; bacterial multicomponent monooxygenase; Benzene; Biodegradation; Bioremediation; Cadmium; Carbon; Catabolism; Catechol; Catechol 1,2-dioxygenase; Catechol 2,3-dioxygenase; Chromosomes; Contamination; Crude oil; Cupriavidus metallidurans; Degradation; Enzymes; Experiments; Gene expression; Genomes; Heavy metals; Hydrocarbons; Intermediates; Mercury; Mercury (metal); Microorganisms; Minimum inhibitory concentration; Oil pollution; Phenols; Phylogenetics; Polluted environments; Silicones; Transcription; United States > US; Germany; cadmium; bacterial multicomponent monooxygenase; aromatic catabolism; mercury; Cupriavidus metallidurans; benzene
• ISSN: 2076-2607; 2076-2607
• DOI: 10.3390/microorganisms10020484

Heavy metal co-contamination in crude oil-polluted environments may inhibit microbial bioremediation of hydrocarbons. The model heavy metal-resistant bacterium CH34 possesses cadmium and mercury resistance, as well as genes related to the catabolism of hazardous BTEX aromatic hydrocarbons. The aims of this study were to analyze the aromatic catabolic potential of CH34 and to determine the functionality of the predicted benzene catabolic pathway and the influence of cadmium and mercury on benzene degradation. Three chromosome-encoded bacterial multicomponent monooxygenases (BMMs) are involved in benzene catabolic pathways. Growth assessment, intermediates identification, and gene expression analysis indicate the functionality of the benzene catabolic pathway. Strain CH34 degraded benzene via phenol and 2-hydroxymuconic semialdehyde. Transcriptional analyses revealed a transition from the expression of catechol 2,3-dioxygenase ( ) in the early exponential phase to catechol 1,2-dioxygenase ( and ) in the late exponential phase. The minimum inhibitory concentration to Hg (II) and Cd (II) was significantly lower in the presence of benzene, demonstrating the effect of co-contamination on bacterial growth. Notably, this study showed that CH34 degraded benzene in the presence of Hg (II) or Cd (II).