Obligate anaerobes do not need or use oxygen as a nutrient. In fact it is a toxic substance to them which either kills or inhibits their growth. Thioglycollate allows obligate anaerobes to grow...
Because they die in the presence of catalase. They also die in the presence of oxygen, due to the absence of superoxide dismutase and catalase. It converts the lethal superoxide inside their cells...
A faculative anaerobe (or faculative bacteria) is an organism that can grow in either the presence or absence of oxygen. It does not require O2 to grow but it does tolerate its presence.
An obligate...
obligate aerobes require oxygen by using cellular respiration or fermentation in order to survive. obligate anaerobes do not require it and will die if they are exposed to oxygen.