Protective micro-organisms

Resistance to penetration by micro-organisms is covered by EN 374-2 and protection from low temperatures in EN 511. Careful handling and regular inspection are essential since chemicals and abrasion will eventually cause deterioration of gloves. Rinsing in clean water and drying naturally will prolong their life. 

Considerable interest arose during the 1970 s and 1980 s in the use of micro-organisms to produce useful fatty adds and related compounds from hydrocarbons derived from the petroleum industry. During this period, a large number of patents were granted in Europe, USA and Japan protecting processes leading to the production of alkanols, alkyl oxides, ketones, alkanoic adds, alkane dioic acids and surfactants from hydrocarbons. Many of these processes involved the use of bacteria and yeasts associated with hydrocarbon catabolism. 

Wooden hatch covers may support and encourage growth, particularly of fungi, and powders, caked onto the stirrer shaft and lid, moistened with condensation and not biocidally protected, can also become colonised by micro-organisms. 

The human and environmental protection goals in EUSES are human populations (workers, consumers, and man exposed via the environment) and ecological systems (micro-organisms in sewage treatment systems, aquatic ecosystems, terrestrial ecosystems, sediment ecosystems, and predators). Repeated dose toxicity, fertility toxicity, maternal toxicity, developmental toxicity, carcinogenic risk, and lifetime cancer risk can be calculated for the cases that literature data is available. 

Natural resins are substances with a high viscosity, semisolids or solid and insoluble in water. They are formed in the so-called resiniferous canals of several trees. Many varieties of plants spontaneously exude resins as a product of their metabolism, to protect themselves against excessive loss of water and attack from micro-organisms. 

EQA for Food Microbiology Health Protection Food borne micro-organisms... 

The flow rate and concentration of wastewater do not remain constant but vary during the course of the day and are also dependent on the time of year. If the flow rate is too high, loss of micro-organisms by washout may occur in secondary treatment processes. If the flow rate is too low, then the lack of nutrients will lead to a reduction of the micro-organism population. Wastewaters entering a treatment plant usually flow first into an equalisation basin, so that the flow rate out of the basin is maintained constant, or between prescribed limits, to protect the subsequent processes. The equalisation tank also reduces the effect of toxic shocks on the biological processes within the main treatment plant. 

The efficacy of chemical and photochemical decolourization of dyes in the effluent of textile factories has been proved many times. However, in the majority of cases these methods are relatively expensive and the solid catalysator used for the oxidation sometimes presents a new problem for environmental protection. Microbiological methods are less expensive, the dyes are decomposed to small organic and inorganic molecules which can be taken up by micro-organisms as carbon and nitrogen sources. Also, in the case of microbiological decomposition of dyes, liquid chromatographic techniques can be... 

Short-chain acids accumulate.under anoxic conditions/-which favor fermentative metabolism of bacteria. Such phytotoxins nay damage the plant directly or predispose plants to infection by pathogens. However plant residues nay also be used as substrates for beneficial micro-organisms to produce plant nutrients, soil conditioners, and plant protection chemicals. There is scope to promote the beneficial microbial effects against the harmful by soil management and by inoculation. 

In high-pressure applications these are two main trends of research high hydrostatic pressure treatment (2000-7000 bar) and supercritical CO2 treatment. In both cases the aim is to inactivate the micro-organisms in order to protect and preserve foods, and so to prolong their shelf-life. 

In a departure from the usual study of arsenic metabolites in mammals, Kuehnelt et at. (1997) found mainly arsenate, arsenite and dimethylarsinic acid, and traces of methylarsonic acid and arsenobetaine in ants living close to an arsenic smelter. The low total arsenic levels, about 12.6mg kg-1, in the ants was suggested as indicative of a protective mechanism which prevents the uptake of arsenic from the high ambient levels. The resistance of micro-organisms to arsenic compounds has been reviewed (Cervantes et at., 1994). 

E. Repellents. It is questionable whether a repellent would have any effect on micro-organisms, but they have been studied for application for protecting wood against higher life forms. The amount of damage to wooden structures each year by animals is considerable. 

Capitalizing on this metabolic difference between higher forms of life and micro-organisms is the basis for this research approach to wood protection. Compounds are available which inhibit the cellulase enzyme systems however, their specificity has not been determined. Mandels and Reese (21,22) found that the extracts from the immature fruit of persimmon or the extract from leaves of bayberry were very effective inhibitors of the cellulase system. At concentration levels of. 00005 and. 00018%, respectively, these two extracts inhibited the cellulase enzymes isolated from Trichoderma viride. It is not known what the active component(s) are in these two extracts. 

Film-forming finishes such as paints, lacquers, and varnishes have long been used to protect wood surfaces. The film-forming finishes are not preservatives they will not prevent decay if conditions are favorable for growth of micro-organisms. 

Production of sulfides. This may involve the production of FeS, Fe (OH)2 etc. and an aggressive chemical agent such as hydrogen sulfide (H2S) or acidity. Micro-organisms may also consume chemical species that are important in corrosion reactions (e.g., oxygen or nitrite inhibitors). Alternatively, their physical presence may form a slime or poultice, which leads to differential aeration cell attack or crevice corrosion. They may also break down the desirable physical properties of lubricating oils or protective coatings. (Stott)5... 

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