BIOLOGY MICROBIO-LAB_FINAL_STUDY_GUIDE. 2022

LAB FINAL STUDY GUIDE Exercise 23 – Bio chemical tests 1. Experiment: CATALASE PRODUCTION a. Type of Medium: Nutrient Agar Slant b. Enzymes: Catalase c. Substrate: Hydrogen Peroxide d. Potenital Products: H20, 02 e. Reagents: 3% Hydrogen Peroxide - Expected Results: S. auerus will produce a positive result for catalase and will produce bubble. If negative no bubbles present - Positive Control: Staphylococcus aureus - Color Change: No color change 2. Experiment: DURHAM TUBE SUGAR FERMENTATION a. Type of Medium: GLUCOSE, LACTOSE, MANNITOL BROTH b. Enzymes: c. Substrate: glucose, lactose, mannitol d. Potenital Products: Presence of Acid and/or gas e. Reagents: - Expected Results: Organism ferments sugar to produce acid. Medium will turn from RED to Yellow. If organism produces gas, a gas bubble will be seen in the inverted tube thus a positive result - Positive Control: Escherichia coli - Color Change: Red to Yellow 3. Experiment: MIXED ACID FERMENTATION/ METHYL RED TEST a. Type of Medium: MR-VP b. Enzymes: Formic Hydrogenylase c. Substrate: glucose, formic acid d. Potenital Products: Lactic, acetic, succinic, and formic acids, ethanol, carbon dioxide and hydrogen gas if glucose is fermented in MR-VP medium e. Reagents: Methyl Red - Expected Results: E. Coli will turn red immediately after adding 3-4 drops of methyl red. If negative, MR-VP will remain light yellow - Positive Control: Escherichia coli - Color Change: + for Methyl Red – turn red 4. Experiment: BUTANEDIOL FERMENTATION/VOGES-PROSKAUER TEST a. Type of Medium: MR-VP-E b. Enzymes: c. Substrate: d. Potenital Products