Bioreactor – Obtaining The Foreign Gene Product

Bioreactor – Obtaining The Foreign Gene Product

May 24, 2023, 16:45 IST

This device was designed to support biologically functional environments. It could also be described as a vessel used to carry out a chemical reaction. This procedure uses living things and materials that these microorganisms' biochemical processes have produced. They fall into two categories: aerobic and anaerobic. They are typically cylindrical, come in various sizes, and are made of stainless steel. It can also be referred to as a vessel designed to support the development of cells or tissues. Regarding bioreactor classifications, these bioreactors can be categorised as a batch, fed-batch, or continuous depending on how they operate.

Introduction

The efficient use of microorganisms for the production of essential commodities like cheese, bread, chocolate, beer, and coffee, tea, antibiotics, and various other primary and secondary metabolites has been made possible in recent years by advancements in fermentation technology and microbial biotechnology. These products arise from the microorganisms' capacity to ferment particular metabolites into the desired product.

It is necessary to utilise a regulated environment that offers favourable circumstances for growth to produce the desired product and encourage the growth of microorganisms. This includes maintaining the right pH, temperature, airflow, flow rates for the culture medium, and agitation rate, among other things. Such production is carried out in a sizable tank or vessel known as a bioreactor, which enables the synthesis of vast quantities of a product by mass-producing microorganisms. The required product will be produced by microorganisms that are given the right environment in the bioreactor to develop and may then be purified. Every one of the millions of cells per unit of space utilised in a bioreactor is a micro-bioreactor in and of itself.

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Bioreactor Types

The main tank or vessel, a cooling and heating system, a sophisticated aeration system, feed ports, a foam control system, and a waste port are the components of a typical bioreactor.

There are various types of bioreactors:

The batch reactor

Since the system is straightforward and closed after the tank has been vaccinated, no additional input or output is permitted. Over time, waste materials begin to accumulate, and nutrients and oxygen levels start to decrease.

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Continuous Stirred Tank Bioreactors (CSTRs)

Continuous input and output are characteristics of this type of bioreactor. To achieve this, the culture medium containing the necessary nutrients and reactants is continuously fed into the bioreactor, and the products of the bio-reaction are simultaneously extracted from the tank. So, these tanks are used for continuous chemical processing.

1. Photobioreactors

These bioreactors stand out from the rest because they are constructed of translucent materials like glass or plastic. These flat-panel or tube-shaped bioreactors are lit by natural or artificial light, promoting the growth of photosynthesis-dependent microbes.

2. Airlift Bioreactors

These bioreactors are particularly useful when working with aerobic cell cultures or when the desired outcome is a gaseous substance. The vessel's contents are stirred up with gas. The gas fed into the vessel is also used to add new materials or remove metabolic molecules produced by the microbial cells.

3. Fixed-bed bioreactors

In these bioreactors, the reacting cells are immobilised to a surface of densely packed solid particles. The solid particles could either be porous or not.

Bioprocessing Steps

Using living microbial cells to produce desired products is called a "bioprocess." The ability of the microorganism to grow in the physicochemical environment provided to it determines whether a bioprocess is successful.

The three P's—the three steps that make up a typical bioprocess—are

1. Preparation, also known as "upstream processing," entails the preparation of all supplies and machinery needed for the production process. Additionally, air purification and equipment sterilisation are involved.

• The discovery and creation of desirable strains. Various techniques are used to improve strains as well.
• The creation of ideal conditions for culture to grow and produce the desired results.

2. Production is the primary stage during which bioprocessing takes place. The cells' reaction to the surrounding environment forms the desired metabolic product. During this phase, the cells are constantly dividing and metabolising.
3. Purification, also known as "downstream processing" or product recovery, separates the desired product from the rest of the medium, removes impurities, and then purifies the resultant product.

Steps in Obtaining Foreign Gene Products

Microbial biotechnology entails the application of biotechnology principles to microorganisms to process them as desired to produce the necessary products. These microbes may be recombinant strains produced through genetic engineering, mutant strains from laboratory cultures, or naturally isolated strains.

The procedures to obtain foreign gene products are as follows:

• Isolating the desired gene.
• Finding an appropriate vector for carrying the desired gene. Using ligase, the gene is inserted into the vector. Thus, "recombinant DNA" is produced.
• The introduction of the r-DNA into a suitable host, such as a bacterial cell. The cell now contains the "foreign gene."
• Select recombinant cells.
• Desired protein or metabolite expression by recombinant cells.

Advantages of Bioreactors

Bioreactors are useful tools that allow microorganisms to grow under regulated conditions to produce the required output. It promotes ideal growing conditions by enabling control over variables like pH, nutrition concentration, oxygen concentration, temperature, etc. Since practically everything is mechanised, labour costs are also reduced.

Applications of Bioreactor Process

1. The production of secondary metabolites such as lovastatin, penicillin, and cyclosporin-A.
2. Production of dairy products that undergo fermentation, such as cheese, buttermilk, yoghurt, etc.
3. The process through which citric acid, lactic acid, acetic acid, and other organic acids are produced
4. Production of vital enzymes such as lipase, xylanase, and laccase.
5. In some cases, the creation of microbial cells rather than their end products takes place in bioreactors. This is seen in the creation of yeast, lactobacillus, single-cell proteins, etc.
6. Mammalian cells are also cultured in bioreactors.
7. Photobioreactors are used to grow algae and cyanobacteria for biofuels, bioplastics, nutraceuticals, and other products and treat wastewater.

Bioreactor: FAQs

Q1. What kind of substance does the ideal bioreactor consist of?

Ans. The material used to construct bioreactors should be non-corrosive and withstand steam sterilisation, high pressure, and pH changes.

Q2. What strain improvement techniques are used in a bioprocess?

Ans. Various techniques such as protoplast fusion, genome shuffles, mutation, and recombination are used to enhance strains in a bioprocess.

Q3. In a photobioreactor, what kind of microorganisms are grown?

Ans. Photosynthetic cyanobacteria or microalgal cultures are grown in photobioreactors.

Q4. What types of bioplastics are made by microorganisms, question?

Ans. Plastics made by microbes are called polyhydroxyalkanoates (PHAs), including polyhydroxy butyrate (PHB).

Q5. How do primary and secondary metabolites differ from one another?

Ans. Primary metabolites are produced during the growth phase and are essential to the organism's ability to grow and reproduce. Primary metabolites give rise to secondary metabolites. These substances serve an ecological purpose but have no impact on an organism's capacity for growth or reproduction.