How Bioreactors Transfer Foreign Genes: Methods and Benefits
What is a Bioreactor?
This is a device that has been made to sustain biologically functioning surroundings. It may also be defined as a vessel in which a chemical process is executed. This process includes organisms and biochemically functioning material extracted from these microorganisms. They can be divided into aerobic and anaerobic. They are usually cylindrical in shape and are of various sizes generally composed of stainless steel. It may also be termed as a vessel that has been made to support the growth of cells or tissues. As far as classifications of bioreactors are concerned, depending on their mode of functioning, these bioreactors can be classified as a batch, fed-batch or continuous.
Types of Bioreactors Processes
There are several bioreactor types and applications, let us see what the bioreactor uses are –
Photobioreactor
This type of bioreactor requires a source of light to carry out the process. You could practically call any such translucent vessel as a photobioreactor. However, this term is more appropriate for enclosed storage space instead of an open system like a pond or a tank. They are used for the growth of organisms like algae, moss plants, cyanobacteria. They need light energy. Other than light, they do not need any kind of sugar or lips.
Sewage Treatment
This requires bioreactors for the cleaning purpose. Most of these systems are designed to utilize chemically inert substances with a large surface area. This helps in the growth of the biological film. Removal of the extra-biological film occurs in setting tanks or systems known as cyclones. Aerators are devices that provide oxygen to the sewage and biota for the sludge to become active. After which it is incorporated in the biological component.
Bioreactors for Specialized Tissues
A bioreactor can be used to ferment ethanol from corncob waste. Many mammals have cells and tissues which require a large surface area or a good support system for it to develop and grow. Higher organisms, which are known as auxotrophic, also need special growth support. This is a serious task when a huge quantity of cells is required to be cultured for therapeutic making reasons.
What are the Types of Bioreactors Found?
There are six kinds of bioreactors present, i.e. -
(1) Continuous Stirred Tank Bioreactors
(2) Bubble Column Bioreactors
(3) Airlift Bioreactors
(4) Fluidized Bed Bioreactors
(5) Packed Bed Bioreactors and
(6) Photo-Bioreactors.
What is Bioreactor Cell Culture?
The vessels designed for this purpose execute a biological function and are used in the culturing of aerobic cells, which in turn is done to perform cellular or enzymatic deactivation.
Interesting Facts about Bioreactors
The bioreactor was invented by Wolf, Schwarz, and Trinh. These three won the NASA "Inventor of the Year" for the interesting creations. The year 1990 saw Anderson and Schwarz licensing patents for the wall bioreactor technology that they created.
Bioreactors help in the survival of cells by sufficient delivery of necessary nutrients throughout the process. Bioreactors also help in tissue structure and organization.
In US dollars, Bioreactors can cost around $10,000 to install, and it works perfectly for around 10 years, after which the woods that have chipped off are required to be replaced.
A bioreactor process undergoes majorly three phases — upstream processing, bioreaction, and downstream processing — to transform the raw material into the finished product.
FAQs on Bioreactor Obtaining Foreign Gene: Types, Uses & Steps
1. What is a bioreactor and what is its primary function in biotechnology?
A bioreactor is a large vessel, typically ranging from 100 to 1000 litres, designed to support a biologically active environment. Its primary function in biotechnology is to carry out chemical processes involving microorganisms, plant, or animal cells on a large scale. The goal is to provide optimal growth conditions for these cells to produce a desired product, such as a recombinant protein, enzyme, or antibiotic.
2. What are the key steps involved in obtaining a foreign gene product using recombinant DNA technology?
The process of obtaining a foreign gene product involves several key steps as per the CBSE 2025-26 syllabus:
- Isolation of the desired gene: The gene of interest is identified and isolated from the source organism.
- Creation of recombinant DNA (rDNA): The isolated gene is inserted into a suitable vector (like a plasmid) using enzymes.
- Transformation: The rDNA is introduced into a host organism, such as E. coli, which is now considered a recombinant cell.
- Large-scale culturing: The recombinant host cells are grown in a bioreactor under optimised conditions to multiply and produce the foreign protein in large quantities.
- Downstream Processing: The desired product is extracted, purified, and formulated from the bioreactor culture.
3. What optimal growth conditions must a bioreactor provide to maximize the yield of a desired protein?
A bioreactor provides the optimal conditions necessary for achieving the desired product. These include:
- Temperature: Maintaining a specific temperature range for cell growth and enzyme activity.
- pH: A pH control system to keep the culture medium at the ideal acidity or alkalinity.
- Substrate: A continuous supply of nutrients (like carbon and nitrogen sources) for the cells to grow.
- Salts and Vitamins: Essential micronutrients required for cellular metabolism.
- Oxygen: An aeration system to supply sterile air for aerobic processes.
4. What are the main types of bioreactors mentioned in the NCERT Class 12 syllabus?
The most commonly used bioreactors are of the stirring type. As per the NCERT syllabus, the two main types are:
- Simple stirred-tank bioreactor: This is a cylindrical vessel with a curved base to facilitate the mixing of contents. It uses a motor-driven agitator system to ensure even mixing and oxygen availability.
- Sparged stirred-tank bioreactor: In this type, sterile air is bubbled (sparged) through the culture medium. This increases the surface area for oxygen transfer, making it more efficient.
5. Why is a simple stirred-tank bioreactor often preferred for large-scale production?
A simple stirred-tank bioreactor is often preferred because its design ensures efficient and even mixing of the culture medium. The agitator system prevents cells from settling and ensures that nutrients and oxygen are uniformly distributed throughout the vessel. This homogeneity helps in maintaining consistent growth conditions, which is crucial for maximizing the yield and quality of the final product on an industrial scale.
6. What is downstream processing and why is it a critical step after using a bioreactor?
Downstream processing refers to the series of steps required to separate and purify the desired product from the bioreactor's culture broth. This is a critical step because the product synthesized in the bioreactor is mixed with other cells, media components, and by-products. The process includes steps like centrifugation, filtration, chromatography, and formulation. Without effective downstream processing, the final product would not be pure, stable, or suitable for its intended use, such as in medicine.
7. How does a sparged stirred-tank bioreactor differ from a simple stirred-tank bioreactor in its method of oxygenation?
The primary difference lies in how oxygen is introduced and distributed. In a simple stirred-tank bioreactor, an agitator mixes the surface air into the culture. In contrast, a sparged stirred-tank bioreactor dramatically increases the oxygen transfer area by bubbling sterile air directly through the culture from the bottom. This 'sparging' creates a larger interface between gas and liquid, leading to more efficient oxygenation.
8. Beyond producing proteins, what are other significant applications of bioreactors in industries like pharmaceuticals and food processing?
While producing recombinant proteins is a major application, bioreactors are vital for many other industrial processes. Key examples include:
- Pharmaceuticals: Large-scale production of antibiotics, vaccines, and monoclonal antibodies.
- Food Processing: Fermentation processes to produce beverages like beer and wine, as well as products like yogurt.
- Biofuels: Production of ethanol and other biofuels from microbial fermentation of biomass.
- Waste Treatment: Using microorganisms in bioreactors to break down industrial and municipal waste.
9. What challenges can arise during the large-scale culturing of recombinant cells in a bioreactor?
Several challenges can occur during large-scale culturing in a bioreactor. A primary concern is maintaining sterility to prevent contamination by unwanted microbes, which can compete for nutrients and spoil the product. Other challenges include ensuring a consistent oxygen supply to all cells in a large volume, managing foam production, and preventing the loss of the recombinant plasmid from the host cells over multiple generations. Proper bioreactor design and precise process control are essential to overcome these issues.
