Microaerophile

tests for oxygen requirements of microorganisms

1. Thioglycolate medium Anaerobic bacteria can be identified by growing in test tubes of Thioglycolate broth. TEST FOR OXYGEN REQUIREMENTS OF MICROORGANISMS

2. Effect of thioglycolate broth on different bacteria .

3. Obligate Aerobes :- needs oxygen because they cannot ferment or respire anaerobically. They gather at top of the test tube where oxygen concentration highest .

4. Obligate anaerobe :- Are poisioned by oxygen so they gather at the bottom of the test tube where oxygen concentration is lowest.

5. Facultative anaerobes:- Can grow with or without oxygen because they can metabolise energy aerobically or anaerobically. They gather mostly at the top because aerobic respiration generates more ATP than either fermentation or anaerobic respiration

6. Microaerophile :- Needs oxygen because they cannot ferment or respire anaerobically. However, they are poisoned by oxygen. They gather in upper part of test tube but not very top .

7. Aerotolerant :- Do not require oxygen as they metabolise energy anaerobically. Unlike obligate anaerobes, however they are not poisioned by oxygen. They can be found evenly spread throughout the test tube.

8. Campylobacter , a type of capnophie A Miacroaerophile is a microorganism that requires oxygen to survive , but requires env’s Containing lower levels of oxygen than present in atmosphere. (typically 2-10% of oxygen) Many microaerophiles are capnophiles requiring an elevated concentration of carbondioxide (ex.- 10% in case of campylobacter species).