Fermentation process conditions

Although, in the production of CGTase, the ability of strains to produce enzyme is the determinant factor, the effect of the fermentation process conditions on the production of enzymes is also crudal. Fermentation conditions include not only the composition of the medium, but also temperature, pH, aeration rate, agitation and other factors, and are of interaction and mutual restraint, with appropriate coordination among the said conditions. Therefore, on condition that the production strain is appropriately chosen, the control of the fermentation process is a key factor for the final output. 

With the proper ratio of nutrients and oxygen feed, a water-soluble polymer is produced and accompanied by growth in the microorganism population. Both contribute to the viscosity of the medium and this limits the production process. Fermentation processes require more strenuous mixing and control conditions. 

Biological—Biochemical Processes. Fermentation is a biological process in which a water slurry or solution of raw material interacts with microorganisms and is enzymatically converted to other products. Biomass can be subjected to fermentation conditions to form a variety of products. Two of the most common fermentation processes yield methane and ethanol. Biochemical processes include those that occur naturally within the biomass. 

Traditionally, the upstream fermentation and cell culture processes have been viewed as being distinct from the subsequent downstream processing and purification steps, and the two different sets of processes nave been optimized individually. In some instances, careful consideration of the conditions used in the fermentation process, or manipulation of the genetic makeup of the host, can simplify and even... 

A major breakthrough in the fermentation process came in 1916 - 1920 when it was found that Aspergillus niger grew well at pH values below 3.5, producing citric add in days rather than weeks. The faster incubation and highly add conditions (often below pH 2.0) also served to minimise potential problems caused by contamination. 

Table 8.7 The most important process conditions for the production of L-phenylalanine by direct fermentation precursor addition, phenylpyruvic add (PPA) bloconversion, acetamidocinnamic add (ACA).

To answer these questions, at first mass balance is required to determine conversion and how much air to supply into the fermentation broth. The substrate consumption or production rates must be set as a start. To demonstrate suitable answers to the above statements, we may approach the questions by reviewing a few biological processes and illustrating all the assumptions and process conditions. 

Normally, fermentation processes can be classified depending on the objective of study. For example, in terms of products fermentation is divided into 4 types, namely, microbial cell, microbial enzyme, microbial metabolite and transformation process. If considering due to its contaminating conditions, it will be classified into 3 types septic, semi-septic and aseptic fermentation. However, in general, the fermentation processed are classified into 3 types as follows. 

Amino adds find apphcations as ingredients of infiision solutions for parenteral nutrition and individnally for treatment of specific conditions. They are obtained either by fermentation processes similar to those used for antibiotics or in cell-fiee extracts employing enzymes isolated fiom bacteria (Table 25.1). Details of the mar and varied... 

In Tobacco. At the time of harvesting, fresh tobacco leaves do not contain measurable amounts of nitrosamines (<5 ppb). However, these compounds are formed during curing, aging and fermentation. Their concentrations depend primarily on the content of proteins, alkaloids, agricultural chemicals and nitrate in the tobacco, as well as on the processing conditions which lead to the reduction of the nitrates. 

A chemical reactor is an apparatus of any geometric configuration in which a chemical reaction takes place. Depending on the mode of operation, process conditions, and properties of the reaction mixture, reactors can differ from each other significantly. An apparatus for the continuous catalytic synthesis of ammonia from hydrogen and nitrogen, operated at 720 K and 300 bar is completely different from a batch fermenter for the manufacture of ethanol from starch operated at 300 K and 1 bar. The mode of operation, process conditions, and physicochemical properties of the reaction mixture will be decisive in the selection of the shape and size of the reactor. 

These energy-producing reactions are termed respiration processes. They require the presence of an external compound that can serve as the terminal electron acceptor of the electron transport chain. However, under anaerobic conditions, fermentation processes that do not require the participation of an external electron acceptor can also proceed. In this case, the organic substrate undergoes a balanced series of oxidative and reductive reactions, i.e., organic matter reduced in one step of the process is oxidized in another. 

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