Aerobic reactors play a major role in the emerging industrial trends of biotechnology. These reactors provide numerous benefits in the form of valuable products that range from peptides to proteins, to organic acids and antibiotics. Aerobic reactors details on how cells use oxygen to generate products that have industrial significance. The primary goal is to understand how microorganisms respond to various system-level changes such as growth rate, cell morphology, ATP accumulation, cell concentration, extracellular product secretion, and adaptation to environmental conditions. Biotechnology associated with microorganisms enhances the productivity of microbial medicines. Aerobic reactors produce useful enzymes or hormones that enable stem cells to be differentiated from blood cells.
Biotechnology associated aerobic reactor technique combine human genome and bacterial genome sequencing to observe bacterial pathways. These pathways should be able to provide high levels of commercially useful molecules. These techniques are perfected microbially for generating pharmaceuticals and biopharmaceuticals products. These techniques were developed for a period of 30 years and aid in redirecting the metabolic pathways, analyzing the different pathways, and inserting the pathways in bacteria or yeast for generating biofuels such as long-chain acids, ethanol, and butanol. These techniques also insert multiple genes into microorganisms so that enzyme hydrolysis occurs.
Tools and Pathways
When these pathways combine with microorganisms, which are modified to ferment glucose, pentose and xylose to ethanol, a self-replicating, multi-functional biocatalyst microorganism is obtained. This technique is name as consolidated bioprocessing (CBP).
This technique aims to achieve fermentation and saccharification in a microorganism. Non-food renewable resources are the usual feedstocks for this technique and since these feedstocks contain recycled carbondioxide, they offer a huge potential in mitigating the generation of carbondioxide. Genome sequencing combination includes analytical tools that are developed for human genome project for observing cellular metabolism, gene amplification; and screening cells using molecular markers. These tools are being developed since the 1970s.
These tools have enabled scientists to develop therapeutically valuable compounds from microbial, dead cells, and enzymes. These techniques are sometimes referred as direct evolution, since the application tools are easily available through chemical compound supply houses containing enzymes and reagents that direct or redirect a microorganism's metabolic machinery in producing products over other products. The process is not simple as it seems, since several enzymes in the metabolic pathways change certain aspects of the cell's metabolism. Hence, screening the transformed microorganisms proves to be a continuing challenge. Screening microorganisms is considered an evolutionary approach where a microbe is identified, propagated, modified, and submitted to the process.
Fermentation Techniques under Limited Oxygen Supply
Fermentation techniques that do not require oxygen for compound production were developed in recent times. These fermentation techniques used a carbon source called the glucose to control the rate and concentration of cell product and mass. If oxygen was required for cell metabolism, it was assumed that it was present in adequate quantities to meet the metabolic requirements of the microorganism. For example, in ethanol production, oxygen was neither supplied nor excluded intentionally from the fermentation process. Once the fermentation process began, carbondioxide that generated as a by-product displaces the oxygen and removed from the fermentation vessel as and when it forms.
Most microorganisms require oxygen to be provided by sparging air in the fermentation bioreactor. In an aerobic bioreactor, rigorous agitation and air bubbling is carried out through a manifold. The oxygen concentration inside the fermentation media is 8 ppm.
Once steady cell-growth occurs, oxygen concentration reaches zero even when the liquid medium is aerated vigorously. In an aerated fermentation, cell mass increases to a point where oxygen is quickly removed from the fermentation media. This condition called as the oxygen- limiting condition further increases the viscosity of the broth due to cell structure and high cell concentration.
The higher the viscosity the difficult the broth becomes to mix and stir. This results in decreased oxygen concentration in the broth. This in turn changes the metabolism of the cell. A fermentation vessel requires maximum oxygen in most cases. For this purpose, both spargers and agitators are used on both production scales and laboratory.
Aerobic bioreactors aid in understanding cell metabolism and the changes associated outside the cell. In some cases, scientists have tried to understand phenomenological response to environmental changes. This response enables a microorganism to dominate diverse cultures.
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