Bioreactors

Bioreactors are specialized containers or setups used to facilitate the controlled development of bacteria or cells. There are various types of bioreactors including stirred tank bioreactors and photobioreactors. Bioreactors are also known as fermenters in which the fermentation process occurs.

Bioreactors class 12 covers basic concepts which are important for understanding this process. In this article, we will cover bioreactor uses, bioreactor parts and their functions, and more.

What is Bioreactor?

Bioreactor Definition: Bioreactors are a specialized tank or system that supports the development of microorganisms or cells under regulated circumstances

In the context of microbial fermentation operations, where microorganisms transform substrates into useful products like drugs, enzymes, biofuels, or other biochemicals, bioreactors are sometimes referred to as fermenters. These containers are made to give regulated circumstances, including temperature, pH, oxygen supply, and nutrient availability, that promote the development and activity of the organisms. Bioreactors are available in a variety of sizes and configurations, from massive industrial tanks that may produce tons of goods to smaller laboratory installations.

Bioreactor Diagram

The labelled diagram of bioreactor is given below:

Diagram of Bioreactors

Principles of Bioreactors

The functioning of bioreactors is determined by many essential factors that oversee biological processes, environmental conditions, and the pace of microbial development and manufacturing.

Biological Reactions in Bioreactors

• In bioreactors, biological processes are usually mediated by microbial growth and metabolism, in which microorganisms use substrates to generate desired products.
• These reactions can include a variety of procedures, including cellular metabolism, enzymatic conversions, and fermentation.
• The ideal conditions for these reactions are provided by the bioreactor, which has the right amounts of nutrients, oxygen, temperature, and pH.

Factors Affecting the Performance of a Bioreactor

A number of variables affect how well bioreactors operate, including

• Temperature: Microorganisms require the ideal temperature to be maintained for growth and activity. Certain microorganisms require a particular temperature to function at their best.
• pH: Enzyme activity, microbial growth, and product production are all impacted by pH levels. The ideal circumstances for biological responses must be maintained by keeping pH within the appropriate range.
• Agitation and Mixing: The equal distribution of microbes, oxygen, and nutrients throughout the bioreactor is ensured via agitation. The performance of a bioreactor is improved by proper mixing, which reduces substrate gradients and improves mass transfer.
• Oxygen Level: Aerobic bacteria growth and metabolism depend on oxygen. A crucial factor in the design of a bioreactor is the oxygen transfer rate (OTR), which guarantees an adequate supply of oxygen for microbial activity.
• Nutrient Availability: The development of microorganisms and the production of products depend on an adequate supply of nutrients, including carbon, nitrogen, phosphorus, and trace elements. Bioreactor performance is maximized by nutrient concentration monitoring and control.

Kinetics of Microbial Growth and Product Formation

In bioreactors, microbial growth and product synthesis adhere to certain kinetic patterns, such as

• Microbial Growth Kinetics: There are four stages of growth that microorganisms go through: the lag, exponential, stationary, and death phases. Temperature, pH, substrate concentration, and nutrient availability are some of the variables that affect growth rate.
• Product Formation Kinetics: Specific kinetics are followed in the manufacture of desired products, which are impacted by metabolic pathways, substrate concentration, microbial growth rate, and product inhibition.

Types of Bioreactor

The designs and configurations of bioreactors vary, and each is appropriate for a particular purpose and set of operating parameters. Typical bioreactor kinds are listed below.

Stirred Tank Bioreactors

• Cylindrical containers having an impeller or other stirring gear to stir the contents are called stirred tank bioreactors.
• For microbial fermentation and cell culture procedures, they are extensively utilized.
• Wastewater treatment, biotechnology, pharmaceuticals, and the food and beverage sectors all use stirred tank bioreactors.

Air-lift Bioreactors

• Gas or air injection is used in air-lift bioreactors to provide mixing and circulation inside the vessel.
• They are made up of a draft tube that creates fluid circulation by raising gas bubbles.
• These bioreactors are frequently used for aerobic microbial cultures, which include the synthesis of enzymes, biofuels, and antibiotics.

Packed Bed Bioreactors

• Microbial cells adhere to and develop on solid support materials like beads, pellets, or fibers used in packed bed bioreactors.
• The packed bed allows the substrate solution to pass through, facilitating biological processes.
• Wastewater treatment, bioconversion, and immobilized enzyme reactions are among their applications.

Membrane Bioreactors

• The bioreactor system incorporates membrane filtering technology through membrane bioreactors.
• For very effective wastewater treatment, they combine membrane separation with biological treatment.
• Water reuse and environmental remediation are two common uses for these bioreactors in municipal and industrial wastewater treatment facilities.

Photobioreactors

• Light is used in photobioreactors to power photosynthetic microorganisms like cyanobacteria and algae.
• Their purpose is to enhance photosynthetic production and increase exposure to light.
• Biofuels, wastewater treatment, nutraceuticals, and biomass generation are among the uses for them.

Parts of Bioreactors and Its Function

There are various components of bioreactor which are important for any bioreactor system;

Fermenter Vessel

• Material: Depending on the use and operating needs, bioreactor vessels are often composed of plastic, glass, or stainless steel. Because of its strength, capacity to withstand corrosion, and simplicity of cleaning and disinfection, stainless steel is the material of choice.
• Size: Depending on the operational scale, bioreactors can range in size from laboratory-scale vessels with a few liters to industrial-scale tanks with hundreds of liters or more.
• Design: The vessel’s design affects elements like heat transport, oxygen transfer, and mixing efficiency. Vases with spherical, conical, and cylindrical shapes are common; each has a unique set of benefits for a particular use.

Agitation Systems

Impellers

• Impellers are revolving paddles or blades that stir up turbulence and encourage mixing inside the bioreactor. Agitation systems usually come with them.
• Depending on the necessary amount of agitation and the viscosity of the culture medium, many types of impellers are utilized, including pitched blade turbines, Rushton turbines, and marine impellers.

Spargers

• Devices called spargers are used to aerate culture media by adding air or oxygen.
• To facilitate effective gas-liquid interaction and oxygen transmission, they are made of porous materials or diffusers placed at the bottom of the bioreactor.

Aeration Systems

• Aeration systems facilitate aerobic microbial growth and metabolism by introducing air or oxygen into the culture media.
• Depending on the oxygen requirements of the microorganisms and the particular needs of the bioprocess, either air or oxygen can be used.

Monitoring and Control Systems

• Sensor: Bioreactors are fitted with sensors to keep an eye on important variables including temperature, pH, dissolved oxygen, speed of agitation, and concentration of substrate.
• Controllers: Control systems modify inputs including temperature, pH, agitation speed, and aeration rate to control a number of factors inside the bioreactor.

Sterilization Systems

• Autoclaves: A lot of bioreactors are sterilized with autoclaves, which use pressure and heat to remove microbiological contaminants from the growth media, vessel, and parts.
• Sterilization in Place: Steam-in-place (SIP) or chemical sterilization are examples of in-situ sterilization techniques that may be used in larger industrial bioreactors.

Uses of Bioreactors

Bioreactors are used in a wide range of sectors to generate valuable substances and alleviate environmental issues by utilizing biological processes.

• Antibiotic Production: In order to produce antibiotics through fermentation processes, microorganisms like fungus and bacteria are cultivated in bioreactors. Erythromycin, streptomycin, and penicillin are a few examples.
• Vaccines: Bioreactors are essential for the manufacturing of vaccines because they may be used to cultivate cell cultures or recombinant organisms that will provide antigens or virus particles for use in vaccine formulations.
• Therapeutic proteins: These are produced in bioreactors using recombinant DNA technology and cell culture techniques. Examples of these proteins include insulin, growth factors, and monoclonal antibodies.
• Beverage Fermentation: A variety of drinks, including wine, spirits, and beer, are fermented in bioreactors. During the fermentation process, microorganisms like bacteria and yeast transform carbohydrates into alcohol and other flavorings.
• Enzyme synthesis: Large-scale synthesis of enzymes like lipase, amylase, and protease which are utilized in food processing, baking, brewing, and detergent manufacturing is accomplished in bioreactors.
• Wastewater Treatment: Biological treatment procedures including activated sludge, aerobic and anaerobic digestion, and membrane bioreactors are carried out in wastewater treatment plants using bioreactors.

Difference Between Bioreactor and Fermenter

The difference between bioreactor and fermenter is given below:

Feature	Bioreactor	Fermenter
Definition	A closed system designed to support and control biological processes using living cells or microorganisms	A specific type of bioreactor designed for fermentation processes, which are anaerobic (without oxygen).
Processes	Can facilitate various biological processes like cellular growth, enzymatic conversions, and fermentation	Primarily used for fermentation processes where microorganisms convert sugars or other substrates into products like ethanol, lactic acid, or antibiotics.
Range of Products	Produces a wider range of products including pharmaceuticals enzymes, biofuels, and single-cell proteins	Focuses on producing fermented products like alcoholic beverages, yogurt, cheese, and some biofuels.
Oxygen Requirement	Can operate under aerobic or anaerobic conditions depending on the process	Typically operates anaerobically, although some variations might involve limited oxygen.
Examples	Stirred tank bioreactors, airlift bioreactors, and photobioreactors	Beer fermentation tanks, wine fermentation vats, yogurt production vessels.

Conclusion – Bioreactor

In conclusion, bioreactors are essential components of many different sectors, advancing the fields of renewable energy, food production, medicine, and environmental sustainability. Bioreactors facilitate the efficient manufacture of valuable chemicals, wastewater treatment, bioremediation, and bioenergy generation by precisely controlling biological processes and environmental conditions. This innovation contributes to the development of a more sustainable and inventive future.

FAQs-Bioreactor

What is Bioreactor and its Function?

A bioreactor is a vessel that supports biological processes, providing controlled conditions for the growth of microorganisms or cells to produce desired products or achieve specific outcomes.

What are the 7 Types of Bioreactor?

The seven types of bioreactors are stirred tank, air-lift, packed bed, membrane, photobioreactors, immobilized cell, and fluidized bed.

What are the Principles of Bioreactor?

The principles of bioreactors involve creating optimal conditions for biological reactions, controlling environmental factors, and maximizing microbial growth and product formation kinetics.

What are the Advantages of Bioreactors?

The advantages of bioreactors include precise control over environmental conditions, scalability, and the ability to produce a wide range of valuable products efficiently.

What are the Limitations of Bioreactors?

The limitations of bioreactors include high initial capital investment, susceptibility to contamination, and challenges in scaling up certain bioprocesses.

What are the Parameters of Bioreactor operation?

The parameters of bioreactor operation include temperature, pH, agitation rate, aeration rate, nutrient concentration, and dissolved oxygen levels.

What are the 3 Common Types of Bioreactors?

The three common types of bioreactors are stirred tank bioreactors, airlift bioreactors, and packed bed bioreactors.

What is the Difference Between a Bioreactor and a Fermentor?

The main difference between a bioreactor and a fermentor lies in their purpose; a bioreactor is used for various biological processes, while a fermentor is specifically designed for fermentation processes like brewing or biofuel production.