Microorganisms cultivation condition

Microorganism and cultivation conditions Rhizopus sp. 26R criltivated in 20 g solid substrates composed of wheat bran, rice bran and rice husk (6 12 2) in a plastic bags. Initial pH and moisture content were 5.7 and 58%, respectively. The fungus was incubated at 32°C for 6 days. 

Under anaerobic conditions, various pathways exist for pyravate metabolism which serve to re-oxidize the reduced hydrogen carriers formed during glycolysis. The ultimate acceptor builds up as a waste product in the culture medium. The end-products of the pathways are (1) CO, ATP, and acetate (2) COj and ethanol (3) and CO2 (4) COj and 2,3-butylene glycol (5) COj, Hj, acetone, ATP, and butanol (6) succinate and (7) lactate. The pathway that occurs depends on the microorganism cultivated and the culture. 

A number of different strategies have been described to exploit the biosynthetic potential of myxobacteria and other microorganisms. " As the production of secondary metabolites is often a specific response of the producing organism to the environmental conditions,a simple way to trigger the production of new compounds is to vary the cultivation conditions. Indeed, growth conditions for strains of different myxobacter-ial species in liquid culture have been established, hut even today these procedures are far from routine, and have to be developed specifically for each strain. ... 

The dependence of enantioselectivity in microbial transformations on the cultivation conditions of the microorganisms has also been investigated182-861. The enzymes induced during the growth phase and during starvation are certainly different, therefore the enantioselectivity of the product may be different when two competing enzymes with different enantioselectivities catalyze the reduction. Since the enzyme... 

On-line, in situ fluorometers provide information on the metabolic state of microorganisms by monitoring the intracellular NAD(P)H pool (see also 22.6.1). Some applications of fluorescence measurements are given in Thble 22-2. These probes can be used to monitor suspended as well as immobilized cells. In both cases, environmental and metabolic changes can be detected under real cultivation conditions. 

The present review deals with the characterization of model protein foams and foams of various cultivation media. The suppression of foaming by antifoam agents and their effect on the oxygen transfer rate, microbial cell growth and product formation are discussed. The influence of process variables on the recovery of proteins by flotation without and with surfactants and mathematical models for protein flotation are presented. The effect of cultivation conditions, flotation equipment and operational parameters on foam flotation of microorganisms is reviewed. Floatable and non-floatable microorganisms are characterized by their surface envelope properties. A mathematical model for cell recovery by flotation is presented. Possible application areas of cell recovery by flotation are discussed. 

It is generally accepted that cultivation conditions such as growth time, growth temperature, the composition of the culture medium, or the preseuce/absence of oxygen, or CO2 may exert a noticeable influence on the protein expression of the microorganisms understudy (Anderson etal. 2012 Balazova et al. 2014 Goldstein et al. 2013 Keys et al. 2004 Valentine et al. 2005 Sedo et al. 2013 Sandrin et al. 2013). Moreover, sample preparation and instrument-specific factors may also af-... 

Screening of enzymes expressed in microorganisms, which are found in the environment and cultivated in laboratory, has the merit of finding novel enzymes because the method does not use the sequence information of already-known enzymes. However, an enzyme cannot be found if the microorganism cannot be cultured under laboratory cultivation conditions, or the microorganism does not express the enzyme under certain laboratory cultivation conditions. 

Chloramphenicol may be prepared by fermentation or by chemical synthesis. The fermentation route to chloramphenicol is described in U.S. Patents 2,4B3,B71 and 2,4B3,B92. To quote from U.S. Patent 2,4B3,B92 The cultivation of Streptomyces venezuelae may be carried out in a number of different ways. For example, the microorganism may be cultivated under aerobic conditions on the surface of the medium, or it may be cultivated beneath the surface of the medium, i.e., in the submerged condition, if oxygen is simultaneously supplied. 

A bioreactor is a vessel in which an organism is cultivated and grown in a controlled manner to form the by-product. In some cases specialised organisms are cultivated to produce very specific products such as antibiotics. The laboratory scale of a bioreactor is in the range 2-100 litres, but in commercial processes or in large-scale operation this may be up to 100 m3.4,5 Initially the term fermenter was used to describe these vessels, but in strict teims fermentation is an anaerobic process whereas the major proportion of fermenter uses aerobic conditions. The term bioreactor has been introduced to describe fermentation vessels for growing the microorganisms under aerobic or anaerobic conditions. 

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