Facultative bacteria

Acid producers. Corrosion usually is moderate and localized. Almost all significant attack is associated with anaerobic bacteria (facultative and obhgate), as aerobic acid-producing varieties usually reside near the top of deposits and corrosion products contacting oxygenated waters. Thus, the direct effect on corrosion at metal surfaces is limited. Additionally, although acidic products may be expected to increase corrosion rates, acidity cannot be pronounced in deposits to put it simply, the deposits and corrosion products would dissolve at sufficiently acidic pH. 

Anaerobic bacteria function only in the complete absence of molecular oxygen, using substances such as nitrate ion and sulfate ion as substitutes for O2. Frequently, molecular oxygen is quite toxic to anaerobic bacteria. A third class of bacteria, facultative bacteria, utilize free oxygen when it is available and use other substances as electron receptors (oxidants) when molecular oxygen is not available. 

Table 1. Occvirrence of aerobic bacteria (facultative anaerobes) in red fox anal sac secretions (29,30,31)...

Lactic Acid B cteri. The lactic acid bacteria are ubiquitous in nature from plant surfaces to gastrointestinal tracts of many animals. These gram-positive facultative anaerobes convert carbohydrates (qv) to lactic acid and are used extensively in the food industry, for example, for the production of yogurt, cheese, sour dough bread, etc. The sour aromatic flavor imparted upon fermentation appears to be a desirable food trait. In addition, certain species produce a variety of antibiotics. 

Free-living bacteria are, however, used as the source of the enzyme nitrogenase, responsible for N2 fixation (1,4,26,80), for research purposes because these ate easier to culture. The enzyme is virtually identical to that from the agriculturally important thizobia. These free-living N2-fixets can be simply classified into aerobes, anaerobes, facultative anaerobes, photosynthetic bacteria, and cyanobacteria. 

Facultative bacteria comprise the last group and use free dissolved oxygen when... 

Studies on 4-hydroxybenzoate decarboxylase and 3,4-hydroxybenzoate decarboxylase have been restricted to obligate anaerobic bacteria, C. hydroxy-benzoicum Aside from the obligate anaerobic microorganism, C. hydroxy-benzoicum, very recently facultative anaerobic bacteria, Enterobacter cloacae strains exhibiting high 4-hydroxybenzoate decarboxylase or... 

The occurrence of 4-hydroxybenzoate decarboxylase was also found in facultative anaerobic bacteria, E. cloacae P240, and the enzyme was purified and characterized. The activity of the cell-free extract of E. cloacae P240 was determined to be 13.7 ijumol min (mg protein) at 30°C, which was much higher than... 

During prolonged storage in the laboratory under conditions of nutrient starvation, facultatively oliogotrophic bacteria may be isolated and these display transport systems for the uptake of amino acids and glucose that are coregulated. 

Jagnow G, K Haider, P-C Ellwardt (1977) Anaerobic dechlorination and degradation of hexachlorocyclo-hexane by anaerobic and facultatively anaerobic bacteria. Arch Microbiol 115 285-292. 

Strains of some facultatively heterotrophic and methylotrophic bacteria can use CS2 as sole energy source, and under aerobic conditions also COS, dimethyl sulfide, dimethyl disulfide, and thioacetate (Jordan et al. 1995). It was proposed that the strains belonged to the genus Thiobacillus, though they are clearly distinct from previously described species, and they have now been assigned to Paracoccus denitrificans (Jordan et al. 1997). 

At many sites, the subsurface environment will be anoxic or even anaerobic due to the activity of aerobic and facultatively anaerobic bacteria in the surface layers of the soil. It is therefore essential to take into consideration the extent to which anaerobic degradation may be expected to be significant. Reactions may take place under sulfidogenic or methanogenic conditions, and the occurrence of sulfate at sites containing building material waste and the metabolic versatility of sulfate-reducing bacteria makes them particularly attractive. 

A combination of aerobic and anaerobic organisms appears to increase the severity of infection. Facultative bacteria (such as E. coli) may provide an environment conducive to the growth of anaerobic bacteria.12 Although many bacteria isolated in mixed infections are nonpathogenic by themselves, their presence may be essential for the pathogenicity of the bacterial mixture.3 Facultative bacteria in mixed infections can ... 

Bacteria can grow in two main environments, aerobic and anaerobic. In aerobic treatment, aerobic and facultative bacteria use molecular oxygen as their terminal electron acceptor. The treatment occurs in the presence of a molecular oxygen supply. In anaerobic treatment, anaerobic and... 

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