Microbial, major types

Microbial products of industrial interest can be of several major types. The cells themselves can be the source of interest, as in yeast for baking, or mushrooms cultivated for food. Another source are bacteria used for inoculation in food products, such as lactobacilli in dairy and sausage products. As stated above, in com-... 

NMR spectra of humin from three major types of depositional environments, aerobic soils, peats, and marine sediments, show significant variations that delineate structural compositions. In aerobic soils, the spectra of humin show the presence of polysaccharides and aromatic structures most likely derived from the lignin of vascular plants. However, another major component of humin is one that contains paraffinic carbons and is thought to be derived from algal or microbial sources. Hydrolysis of the humin effectively removes polysaccharides, but the paraffinic structures survive, indicating that they are not proteinaceous in nature. The spectra of humin differ dramatically from that of their respective humic acids, suggesting that humin is not a clay-humic acid complex. 

Callow [1990] has described the use of antifouling paints in conjunction with ships hulls to reduce microbial and macro-fouling, but the principle could be applied to heat exchangers in suitable environments. She defines three major types of antifouling paints. 

Two major types of contamination of concern are associated with microbial pathogens (e.g., bacteria, virus, ciyptospiridium) and chemical or radiogenic elements native to the subsurface enviromnents. Microbial contamination of water supply is a worldwide problem which has far more damaging iimnediate consequences in causing water... 

The second major type of reductive metabolism of anthracyclines is the reduction of 13-0X0 anthracyclines to their 15-dihydro analogs (182,183,244,287-293). This keto reduction reaction at Cl3 appears to be carried out by a wide variety of microbial reductases with broad or low substrate specificity (184,244,287-293). In a potential application of this reductive reaction, Marek et al. (291) demonstrated that immobilized mycelia of Strepltmiycej awreo/ociens strain B-96 can reduce daunonibtcinone to 13-dihydrodaunoru-bicinone. 

Two major types of microbial resistance can be distinguished intrinsic and acquired resistance. Intrinsic (innate) resistance refers to a natural chromosomally controlled property, including physiological adaptation. 

Various mechanisms of electron transfer and linking species have been identified and exploited. Basically there are two major types of linking species (i) soluble compounds (artificial or self-produced mediators), and (ii) compounds bonded to the microbial cell membrane (membrane-bond proteins or nanowires). Accordingly, electron transfer mechanisms from microorganisms to the electrode can be divided into five primary types, which will be discussed in the following section (1) direct cell-surface electron transfer, (2) direct electron transfer via nanowires, (3) electron transfer via exogenous redox mediators, (4) endogenous redox mediators and (5) reduced metabolic products. 

Tetanus occurs when Cl. tetani, ubiquitous in the soil and faeces, contaminates wounds, especially deep puncture-type lesions. These might be minor traumas such as a splinter, or major ones such as battle injury. At these sites, tissue necrosis and possibly microbial growth reduce the oxygen tension to allow this anaerobe to multiply. Its growth is accompanied by the production of a highly potent toxin which passes up peripheral nerves and diSuses locally within the central nervous system. It acts like strychnine by affecting normal function at the synapses. Since the motor nerves of the brain stem are the shortest, the cranial nerves are the first affected, with twitches of the eyes and spasms of the jaw (lockjaw). 

Pharmaceutical products are used in a variety of ways in the prevention, treatment and diagnosis of disease, hi recent years, manufacturers of pharmaceuticals have improved the quality of non-sterile products such that today the majority contain only a minimal microbial population. Nevertheless, a few rogue products with an unacceptable level and type of contamination will occasionally escape the quality control net and when used may, ironically, contribute to the spread of disease in patients. 

There are several chemical compounds found in the waste waters of a wide variety of industries that must be removed because of the danger they represent to human health. Among the major classes of contaminants, several aromatic molecules, including phenols and aromatic amines, have been reported. Enzymatic treatment has been proposed by many researchers as an alternative to conventional methods. In this respect, PX has the ability to coprecipitate certain difficult-to-remove contaminants by inducing the formation of mixed polymers that behave similarly to the polymeric products of easily removable contaminants. Thus, several types of PX, including HRP C, LiP, and a number of other PXs from different sources, have been used for treatment of aqueous aromatic contaminants and decolorization of dyes. Thus, LiP was shown to mineralize a variety of recalcitrant aromatic compounds and to oxidize a number of polycyclic aromatic and phenolic compounds. Furthermore, MnP and a microbial PX from Coprinus macrorhizus have also been observed to catalyze the oxidation of several monoaromatic phenols and aromatic dyes (Hamid and Khalil-ur-Rehman 2009). 

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