Clostridia

The fermentative fixing of CO2 and water to acetic acid by a species of acetobacterium has been patented acetyl coen2yme A is the primary reduction product (62). Different species of clostridia have also been used. Pseudomonads (63) have been patented for the fermentation of certain compounds and their derivatives, eg, methyl formate. These methods have been reviewed (64). The manufacture of acetic acid from CO2 and its dewatering and refining to glacial acid has been discussed (65,66). 

The penicillins as natural and semisynthetic agents are used primarily against susceptible Pasteurella sp., staphylococci, streptococci, clostridia, and CoTynebacterium sp. Penicillin is widely used for therapeutic purposes against these organisms and in animal feeds as a growth promoter. The latter effect is considered to be a result of subtie and reversible effects on the gastrointestinal microflora. 

Clostridia are anaerobic bacteria that can produce organic acids. Short-chain organic acids can be quite aggressive to steel. Clostridia are frequently found deep beneath deposit and corrosion-product accumulations near corroding surfaces and within tubercles. Increased acidity directly contributes to wastage. 

Clostridia frequently are found where sulfate-reducing bacteria are present, often in high numbers inside tubercles. A typical microbiological analysis of tubercular material removed from a troubled service water system main is given in Table 6.4. Clostridia counts above 10 /g of material are high enough to cause concern. When acid producers... 

TABLE 6.4 Typical Microbiological Analysis of Tubercular Material Containing High Concentrations of Clostridia ... 

Clostridia are anaerobie, spore-forming rods. The genus eontains a number of dangerous pathogens. 

Penicillin Streptococci, staphylococci, corynebacteria, Clostridia, Listeria Anaerobes... 

Reactions involving carbamyl phosphate in the degradation of arginine in Clostridia, and the fermentation of allantoin by Streptococcus allantoicus... 

The activity of formyl TFIF synthase during the fermentation of purines by Clostridia... 

Attention is directed to two gronps of anaerobic bacteria that display metabolic versatility toward strnctnrally diverse snbstrates—Clostridia and anaerobic sulfate reducers. 

Several Clostridia including Cl. tyrobutyricum. Cl. thermoaceticum, and Cl. kluyveri are able to reduce the double bond of a,p-unsaturated aldehydes, ketones, and coenzyme A thioesters (Rohdish et al. 2001), and are noted in Chapter 3, Part 3. 

Rohdish F, A Wiese, R Feicht, H Simon, A Bacher (2001) Enoate reductases of Clostridia. Cloning, sequencing, and expression. J Biol Chem 276 5779-5787. 

The existence of microaerophilic organisms such as Wolinella succinogenes that was formerly considered an anaerobe or, conversely, the oxygen tolerance of many Clostridia, suggests that such organisms may occupy an ecological niche between the two extremes already noted. 

The carboxylic acid reductase in acetogenic Clostridia such as Clostridium thermoaceti-cum (White et al. 1989 Strobl et al. 1992). 

Tungsten may be incorporated into some proteins of purinolytic Clostridia (Wagner and Andreesen 1987), and into formyhnethanofuran dehydrogenase in Methanobacterium thermoautotrophicum (Bertram et al. 1994). 

The degradation of amino acids has been examined in detail, particularly in Clostridia (Barker 1981), and these investigations have revealed a number of important reactions not encountered in other degradations. 

Elsden SR, MG Hilton, DA Hopwood (1976) The end prodncts of the metabolism of aromatic acids by Clostridia. Arch Microbiol 107 283-288. 

As for the aerobic degradation of pyridines, hydroxylation of the heterocyclic ring is a key reaction in the anaerobic degradation of azaarenes by Clostridia. Whereas in Clostridium barkeri, the end products are carboxylic acids, CO2, and ammonium, the anaerobic sulfate-reducing Desulfococcus niacinii degraded nicotinate completely to CO2 (Imhoff-Stuckle and Pfennig 1983), although the details of the pathway remain incompletely resolved. 

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