Clostridium

There are a number of other media suitable for the growth of clostridia. The most important are Reinforced Clostridial Medium (RGM), Iron Sulfite medium, and Thioglycollate medium. The aim of all these media is to provide an environment of sufficient reducing power to allow anaerobes to grow in the presence of air. Anaerobes will grow on many media if cultured in an anaerobic jar, but this is not a simple process and should be avoided if possible. 

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Nitrates are found in fairly high concentrations in beets, spinach, kale, coUards, eggplant, celery, and lettuce. AdditionaHy, nitrates and nitrites are commonly used in the curing solutions of bacon, ham, and other cured meats. In cured meats, nitrates and nitrites control the growth of microorganisms, particularly Clostridium botulinum, and also serve as color preservatives. 

Clostridium. This geaus is comprised of a heterogeaeous assemblage of obligate, anaerobic, gram-positive, endospore-forming bacteria (21). 

Microbial-enhanced oil recovery involves injection of carefully chosen microbes. Subsequent injection of a nutrient is sometimes employed to promote bacterial growth. Molasses is the nutrient of choice owing to its low (ca 100/t) cost. The main nutrient source for the microbes is often the cmde oil in the reservoir. A rapidly growing microbe population can reduce the permeabiHty of thief zones improving volumetric sweep efficiency. Microbes, particularly species of Clostridium and Bacillus, have also been used to produce surfactants, alcohols, solvents, and gases in situ (270). These chemicals improve waterflood oil displacement efficiency (see also Bioremediation (Supplement)). 

L-homo serine L-methionine-y-lyase Clostridium, Pseudomonas 133... 

Selenocysteine was identified in 1976 (57) in a protein produced by Clostridium stricklandii, and it is thought to be the form in which selenium is incorporated, stoichiometricaHy, into proteins. Studies with rats show that over 80% of the dietary selenium given them is incorporated into proteins, thus selenocysteine takes on metaboHc importance. Selenoproteins having known enzymatic activities contain selenocysteine at the active sites. Two other forms of metabohc selenium are recognized methylated selenium compounds are synthesized for excretion, and selenium is incorporated into some transfer ribonucleic acids (tRNAs) in cultured cells (58). Some of the more important seleno-compounds are Hsted in Table 4. Examples of simple ring compounds are shown in Eigure 4. 

Composition and Methods of Manufacture. The diseases of diphtheria and tetanus are caused by toxHis synthesized by the organisms CoTynebacterium diphtheriae and Clostridium tetanic respectively. Diphtheria and tetanus vacciaes coataHi purified toxHis that have beea iaactivated by formaldehyde to form toxoids. 

Biosynthetic Mechanism. Riboflavin is produced by many microorganisms, m( dtm. A.shhyagossjpii A.sperigiUus sp remothecium ashbyii Candida yeasts, Debaryomjces yeasts, Hansenu/a yeasts, Picbia yeasts, A. tobactor sp, Clostridium sp, and Bacillus sp. 

Fermentative Manufacture. Throughout the years, riboflavin yields obtained by fermentation have been improved to the point of commercial feasibiUty. Most of the riboflavin thus produced is consumed in the form of cmde concentrates for the enrichment of animal feeds. Riboflavin was first produced by fermentation in 1940 from the residue of butanol—acetone fermentation. Several methods were developed for large-scale production (41). A suitable carbohydrate-containing mash is prepared and sterilised, and the pH adjusted to 6—7. The mash is buffered with calcium carbonate, inoculated with Clostridium acetohutylicum and incubated at 37—40°C for 2—3 d. The yield is ca 70 mg riboflavin/L (42) (see Fermentation). 

Arthrobacter hjalinus Pacillus megaterium Butyribacterium rettgeri Clostridium sticklandii Clostridium tetanomorphum Clostridium thermoaceticum... 

Although immediate reactions of anaphylaxis, bronchospasm, and urticaria have been reported, most commonly patients exhibiting an adverse reaction develop a maculopapular rash, usually after several days of therapy. They may also develop fever and eosinophilia (80,219). Cefoperazone (34) and ceftriaxone (39), having greater biUary excretion than other cephalosporins, are associated with an increased risk of diarrhea, which may be caused by selection of cytotoxin producing stains of Clostridium difficile (219). 

M ribosomal protection Neisseria, Mycoplasma, Ureaplasma, Haemophilus, Campylobacter, Clostridium, Enterococcus, Staphylococcus, Streptococcus Gardnerella, Kingella, Eikenella, Veillonella, Tusobacterium, Peptostreptococcus Clostridium difficile. Streptococcus pneumoniae... 

The earhest commercial process to 1-butanol, still practiced extensively in many Third World countries, employs fermentation of molasses or corn products with Clostridium acetobutylicum (11—13). Acetone and ethanol are obtained as coproducts. 

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