Maintaining micro-organisms

This discrepancy is due to die fact that other products such as formate, are formed in very small amounts as byproducts of the metabolic routes leading to L-phenylalanine and polymer synthesis. Of course, part of die glucose is also used for die metabolic activities in the micro-organism necessary to maintain the cells in a viable state, this is termed the maintenance energy requirement... 

Addition of antibiotics to the fermentation broth may be used to avoid problems associated with growth revertants (eg auxotrophic back mutation) ensure that genetic material (eg plasmid DNA) is maintained within the process micro-organism. 

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 activated sludge process, depicted in Fig. 1, involves basically the aeration and agitation of an effluent in the presence of a flocculated suspension of micro-organisms which are supported on particulate organic matter. After a predetermined residence time (usually several hours) the effluent is passed to a sedimentation tank where the flocculated solids are separated from the treated liquid. A reduction of BOD from 250-350 mg IT1 to a final value of 20 mg L-1 is achieved under typical operating conditions. Part of the settled sludge is usually recycled to the aeration tank in order to maintain biological activity. 

Since adult cestodes, freshly removed from a host gut, are invariably covered with a mucus film containing micro-organisms such as yeasts, bacteria and fungi, most workers have used larval stages, which invariably occur in sterile habitats, as initial culture material. Nevertheless, by application of antiobiotics certain species of adult cestodes (e.g. H. diminuta, E. granulosus) may readily be cultured in vitro after removal from the definitive host before the end of the pre-patent period and then maintained in vitro, when egg release is safely contained within the culture vessel (736,811, 867). 

In fermentation reactors, cell growth is promoted or maintained to produce metabolite, biomass, transformed substrate, or purified solvent. Systems based on macro-organism cultures are usually referred as tissue cultures. Those based on dispersed non-tissue forming cultures of micro-organisms are loosely referred as microbial reactors. In enzyme reactors, substrate transformation is promoted without the life-support system of whole cells. Frequently, these reactors employ immobilized enzymes, where an enzyme is supported on inert solids so that it can be reused in the process. Virtually all bioreactors of technological importance deal with a heterogeneous system involving more than two phases. 

Moist-heat sterilization is achieved when water vapor (or, more generically, moist heat, i.e., a suitable combination of temperature and humidity) at a definite temperature is introduced or generated (even indirectly) at the level of the micro-organisms to be inactivated and is maintained in such conditions for a definite time. As explained in detail hereafter, moist-heat sterilization proceeds as an inverse logarithmic progression. Therefore, only a treatment of infinite duration provides absolute certainty that all micro-organisms have been inactivated. 

Pure cultures of microbes also called hanks of microbes Fully genetically identified micro-organisms are stored and used as references for testing laboratories to characterise their homemade strains . They could be compared to banks of pure chemical reference substances. These microbes are living organisms maintained in a few reference laboratories, which will realise the identification work of strains sent by testing laboratories. 

Ophthalmic products have to be manufactured sterile and be free from micro-organisms. Once opened, the sterility of a multidose product must be maintained during its period of use. This is usually required for at least 4 weeks, after which the product is discarded. If the drug itself does not possess antimicrobial properties, then an antimicrobial preservative must be included in the formulation to ensure that any micro-organisms accidentally introduced during use are destroyed. 

Within the next 5 to 10 years, it would probably be possible to make a new infective micro-organism which could differ in certain important respects from any known disease-causing organisms. Most important of these is that it might be refractory to the immunological and therapeutic processes upon which we depend to maintain our relative freedom from infectious disease.5... 

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