Temperature Cell growth

Biomass or mass of living matter, living cells in a liquid solution with essential nutrients at suitable temperature and pH leads to cell growth. As a result, the content of biomass increases with time. 

There several DO probes available. Some well-known branded fermenters, like New Brunswick, Bioflo series and the B. Braun Biotstat B fermenters are equipped with a DO meter. This unit has a 2 litre fermentation vessel equipped with DO meter and pH probe, antifoam sensor and level controllers for harvesting culture. The concentration of DO in the media is a function of temperature. The higher operating temperature would decrease the level of DO. A micro-sparger is used to provide sufficient small air bubbles. The air bubbles are stabilized in the media and the liquid phase is saturated with air. The availability of oxygen is major parameter to be considered in effective microbial cell growth rate. 

Table 3.1 shows the kinetic parameters for cell growth, rate models with or without inhibition and mass transfer coefficient calculation at various acetate concentrations in the culture media. The Monod constant value, KM, in the liquid phase depends on some parameters such as temperature, initial concentration of the carbon source, presence of trace metals, vitamin B solution, light intensity and agitation speeds. The initial acetate concentrations in the liquid phase reflected the value of the Monod constants, Kp and Kp. The average value for maximum specific growth rate (/xm) was 0.01 h. The value... 

On the other hand, Aspergillus FP-180, isolated from spoiled fruit in Mexico, showed a different pattern. At 30 C its growth was similar at pHi of 3.5 to 6.5 (Fig. 1A). However, at 2.5 pHi a decrease of 60% in relation to maximum was obtained. This reduction in growth was more accentuated that those occurred with A. niger. When the temperature was set at 37 C the same picture was observed (Fig IB). However the effect of very acidic pHi (i.e. 2.5) was more evident with a reduction in cell growth of 80 /o at this temperature (Fig. 1B). An important decrease in growth was also found at 3.5 pHi. Cell growth of both strains was favored at 30 C. 

Effect of Temperature on Insect Cell Growth Kinetics... 

Endothelial cells recovered from both the enzyme (trypsin) recovery system (ERS) and the poly(IPAAm) temperature recovery system (TRS) were subcultured and examined comparatively for cell adhesivity, cell morphology and cell growth activity. The most important finding in the subcultured system was that the TRS exhibited much a higher activity of prostacyclin generation than ERS. It is known that prostacyclin generation is an important function of endothelial cells. 

The rate of cell growth is influenced by temperature, pH, composition of medium, rate of air supply, and other factors. In the case that all other conditions are kept constant, the specific growth rate may be affected by the concentration of a certain specific substrate (the limiting substrate). The simplest empirical expression for the effect ofthe substrate concentration on the specific growth rate is the following Monod equation, which is similar in form to the Michaelis-Menten equation for enzyme reactions ... 

Temperature Ihe temperature in a bioreactor is an important parameter in any bioprocess, because all microorganisms and enzymes have an optimal temperature at which they function most efficiently. For example, optimal temperature for cell growth is 37 °C for Escherichia coli and 30 °C for Saccharomyces sp, respectively. Although there are many types of devices for temperature measurements, metal-resistance thermometers or thermistor thermometers are used most often for bioprocess instrumentation. The data of temperature is sufficiently reliable and mainly used for the temperature control of bioreactors and for the estimation of the heat generation in a large-scale aerobic fermentor such as in yeast production or in industrial beer fermentation. 

In the cell fermentation stage of the process, calluses are propagated in a wholly aqueous medium in large fermenters under controlled conditions at ambient temperature and pressure. The feedstock for cell growth consists of renewable nutrients, sugars, amino acids, vitamins, and trace elements. 

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