Metabolism of styrene by Rhodococcus rhodochrous NCIMB 13259

Area of Science:

• Microbiology
• Biochemistry
• Environmental Science

Background:

• Aromatic hydrocarbons like styrene, toluene, ethylbenzene, and benzene are environmental pollutants.
• Microbial degradation pathways are crucial for bioremediation of these compounds.
• Understanding the specific enzymes and intermediates involved is key to optimizing biodegradation.

Purpose of the Study:

• To elucidate the biodegradation pathway of styrene by Rhodococcus rhodochrous NCIMB 13259.
• To identify key enzymes and intermediate metabolites in styrene metabolism.
• To investigate the role of the cis-glycol pathway in styrene degradation.

Main Methods:

• Growth studies using various aromatic hydrocarbons as sole carbon sources.
• Enzyme assays including oxygen consumption, cis-glycol dehydrogenase, catechol dioxygenase, and hydrolase activities.
• Identification of accumulated metabolites using techniques like 18O2 labeling and spectral analysis.

Main Results:

• Rhodococcus rhodochrous NCIMB 13259 utilizes styrene, toluene, ethylbenzene, and benzene as carbon sources.
• Evidence supports a cis-glycol pathway involving styrene cis-glycol and 3-vinylcatechol.
• Key enzymes identified include NAD-dependent cis-glycol dehydrogenase and catechol 2,3-dioxygenase, with 2-vinylmuconate as a dead-end product.

Conclusions:

• Rhodococcus rhodochrous NCIMB 13259 employs a cis-glycol pathway for styrene biodegradation.
• The study identified specific enzymes and intermediates, contributing to the understanding of aromatic hydrocarbon metabolism.
• This knowledge can inform strategies for bioremediation of styrene-contaminated environments.