Dear Researchers,
If a Bacteria shows some specific activity in Aerobic Condition: Dissolved Oxygen = 7 mg/sample (1000 mL), and is also maintaining this specific activity under the condition: Dissolved Oxygen = 0.1 mg/sample (1000 mL), which category shall this bacteria be placed amongst:
1: Facultative
2: Anaerobic.
Note: I need some reference articles dealing with Anaerobiosis.
Looking forward!
Best,
Syed Salman Ali Shah
First, I want to be sure that I understand.
You have a bacteria that is active under aerobic conditions (7 mg/L), and you expect that the same bacteria is active at 0,1 mg/L.
I have a question: are you able to separate the activity of your bacteria between those come from wastewater ???
Also you measure 0,1 mg/L, this is a very low value for a typical DO probe. You need to be sure about this value because It's not far from 0 mg/L and usual DO probe are not very accurate at this range. Normally, in wastewater treatment oxygen become limited for aerobic degradation under 1,5-2 mg/L.
In bacterial metabolism, for strictly anaerobic bacteria, O2 are normally toxic for the bacteria. In facultative bacteria, some can use O2 as final acceptor, or another organic compound as final acceptor (fermentative). Some bacteria can also use O2 or another inorganic final acceptor as NO3 or NO2, SO4 when O2 depletion...
Other concept is anoxic conditions (without O2, but with NO3 or NO2...) this is in link with the Redox potential.
So in your case if the same bacteria is active between 0,1 and 7 mg/L, I would tend to believe that you have a facultative bacteria.
Sorry I don't indicate many references but some keywords.
Yann
0,1mg/100ml = 1mg/L. If 7mg/L = 100% of saturation for atmospheric pressure, 1mg/L = 14,3% of saturation. Such DO concentration is usual even in aerobic fermentations...
Anaerobic definitely not. Oxygen is toxic for these microbes ,as most of them don't posses anti ROS mechanism. How did u measured 0.1 mg O2? It is rarely 1 ppm. Headspace or direct from the liquid?
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