Yeasts aerobic

Full Tanks. A sound tank that is kept adsolutely full cannot have any significant amount of spoilage from film yeast, aerobic bacteria, or the direct effects of oxygen reaction. 

Laboratory Differential) bacteria, yeast aerobic or anaerobic depending on the target of the investigation... 

Refermented with aerobic yeast light (white) flor (Fino) sherries, Spanish man2anilla types, California (etc) submerged culture dry sherry. See... 

Riboflavin is also made by aerobic culturing of Pichiaguilliermondii on a medium containing n-Q g-Q paraffins in a yield of 280.5 mg/L (53). A process employing Pichia yeasts, such as P. miso, P. miso Mogi, or P. mogii, in a medium containing a hydrocarbon as the carbon source, has been patented... 

In the biosynthesis of the thia2ole, cysteine is the common sulfur donor. In yeasts, the C-2 and N may be suppHed by glycine, and the remaining carbons byD-ribulose-5-phosphate [108321-99-9] (50). In anaerobic bacteria, the C-2 andN maybe recmited from tyrosine and the carbons from D-l-deoxyxylulose [16709-34-5] (51), whereas in aerobic bacteria the C-2 and N maybe derived from glycine, as in yeasts 7 (74—76,83—86) (see Fig. 9). 

A suitable means of scale-up for aerobic processes is to measure the dissolved oxygen level that is adequate in small equipment and to adjust conditions in the plant until this level of dissolved oxygen is reached. However, some antibiotic fermentations and the production of fodder yeast from hydrocarbon substrates have very severe requirements, and designers are hard-pressed to supply enough oxygen. 

When excess substrate interferes with growth and/or product formation. One example is the production of baker s yeast. It is known that relatively low concentrations of certain sugars repress respiration and this will make the yeast cells switch to fermentative metabolism, even under aerobic conditions. This, of course, has a negative effect on biomass yield. When maximum biomass production is aimed at, fed batch cultures are the best choice, since the concentration of limiting sugar remains low enough to avoid repression of respiration. 

Aeration required for aerobic growth removes ethanol (produced by yeast growth) from the medium, keeping ethanol levels below inhibitory concentrations, thus giving a higher yield. 

DuPont has developed a process for the manufacture of glyoxylic acid by aerobic oxidation of glycolic acid (Fig. 2.33) mediated by whole cells of a recombinant methylotrophic yeast (Gavagnan et al, 1995). The glycolic acid raw material is readily available from the acid-catalysed carbonylation of formaldehyde. Traditionally, glyoxylic acid was produced by nitric acid oxidation of acetaldehyde or glyoxal, processes with high E factors, and more recently by ozonolysis of maleic anhydride. 

Oxygen levels. Reactions can be carried out under aerobic conditions in which free oxygen is required or under anaerobic conditions in the absence of free oxygen. Bacteria can operate under aerobic or anaerobic conditions. Yeasts, moulds and algae prefer aerobic conditions but can grow with reduced oxygen levels. 

Microbial degradation susceptible to attack by yeasts, fungi, bacteria very susceptible in aerobic conditions... 

The distribution of elements in single-cell non-photosynthetic eukaryotes is probably best seen in terms of the well-defined compartments of yeast. The central cytoplasmic compartment containing the nucleus has many free element concentrations, only somewhat different from those in all known aerobic prokaryotes (Figure 7.7). (The nuclear membrane is a poor barrier to small molecules and ions and so we include the nucleus with the cytoplasm.) We do not believe in fact that the free cytoplasmic values of Mg2+, Mn2+, Fe2+, Ca2+, and possibly Zn2+, have changed greatly throughout evolution. As stressed already there are limitations since free Mg2+ and Fe2+ are essential for the maintenance of the primary synthetic routes of all cells, and changes in other free metal ions could well have imposed... 

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