Cultures can be placed in a solution of 3% hydrogen peroxide (H2O2) to determine if they contain catalase positive species such as staphylococci, which are facultative anaerobes, or catalase negative species such as streptococci, which are aerotolerant and do not contain the catalase enzyme.

Catalase Rapid Test

Catalase is an enzyme that converts hydrogen peroxide (H2O2) to water and oxygen

All organisms that come in contact with ROS must contain at least one of three essential enzymes to detoxify the reduced oxygen to avoid damage; obligate anaerobes do not contain any of these enzymes:
- Peroxidases
- Superoxide dismutase (SOD)
- Catalase 

Detoxifying Reactive Oxygen Species

https://openstax.org/details/books/microbiology/

Microbiology covers the scope and sequence requirements for a single-semester microbiology course for non-majors. The book presents the core concepts of microbiology with a focus on applications for careers in allied health. The pedagogical features of the text make the material interesting and accessible while maintaining the career-application focus and scientific rigor inherent in the subject matter. Microbiology’s art program enhances students’ understanding of concepts through clear and effective illustrations, diagrams, and photographs.

Microbiology is produced through a collaborative publishing agreement between OpenStax and the American Society for Microbiology Press. The book aligns with the curriculum guidelines of the American Society for Microbiology.

OpenStax Microbiology Textbook

Peroxidases act as a catalyst in reactions utilizing electron donors, for example NADH, to oxidize hydrogen peroxide (H2O2) or other peroxides to water.

Peroxidases

Superoxide Dismutase (SOD) is involved in the reaction that neutralizes the damaging superoxide anions produced during aerobic metabolism. Aerotolerant anaerobes contain only SOD, no catalase. 

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