Degradation of alicyclic molecules by Rhodococcus ruber CD4.

Area of Science:

• Microbial metabolism
• Biochemistry
• Environmental science

Background:

• Alicyclic molecules like cyclododecane lack terminal carbons, necessitating unique degradation pathways.
• Bacterial degradation offers a sustainable approach to breaking down recalcitrant organic compounds.

Purpose of the Study:

• To investigate the bacterial degradation pathway of the alicyclic molecule cyclododecane.
• To identify key enzymes and metabolic intermediates involved in cyclododecane breakdown.

Main Methods:

• Isolation and characterization of the cyclododecane-degrading bacterium Rhodococcus ruber CD4 DSM 44394.
• Enzymatic assays to determine the activity and specificity of key enzymes, including Baeyer-Villiger oxygenase.
• Metabolic analysis to identify intermediate compounds such as alcohols, ketones, lactones, and hydroxyalkanoic acids.

Main Results:

• Rhodococcus ruber CD4 DSM 44394 oxidizes cyclododecane to its corresponding alcohol and ketone.
• A Baeyer-Villiger oxygenase catalyzes ring fission of the cyclododecanone intermediate.
• The resulting lactone is metabolized to an omega-hydroxyalkanoic acid, which enters beta-oxidation.

Conclusions:

• The study elucidates a novel bacterial pathway for cyclododecane degradation initiated by subterminal oxidation.
• The identified Baeyer-Villiger oxygenase exhibits broad substrate specificity for larger ring structures.
• This microbial system holds potential for applications in bioremediation and the valorization of recalcitrant cyclic compounds, including coal components.