<P> Fermentation differs from anaerobic respiration in that the pyruvate generated from glycolysis is broken down without the involvement of an electron transport chain (i.e. there is no oxidative phosphorylation). Numerous fermentation pathways exist e.g. lactic acid fermentation, mixed acid fermentation, 2 - 3 butanediol fermentation . </P> <P> The energy yield of anaerobic respiration and fermentation (i.e. the number of ATP molecules generated) is less than in aerobic respiration . This is why facultative anaerobes, which can metabolise energy both aerobically and anaerobically, preferentially metabolise energy aerobically . This is observable when facultative anaerobes are cultured in thioglycollate broth . </P> <P> Examples of obligately anaerobic bacterial genera include Actinomyces, Bacteroides, Clostridium, Fusobacterium, Peptostreptococcus, Porphyromonas, Prevotella, Propionibacterium, and Veillonella . Clostridium species are endospore - forming bacteria, and can survive in atmospheric concentrations of oxygen in this dormant form . The remaining bacteria listed do not form endospores . </P> <P> Examples of obligately anaerobic fungal genera include the rumen fungi Neocallimastix, Piromonas, and Sphaeromonas . </P>

Where would an obligate anaerobe be found growing in a tube of thioglycollate broth