Professional Manufacturers Mbr Membrane Bioreactor

2022-03-17

Bioreactors are devices designed to simulate the growth environment of microorganisms and cells in natural ecosystems, creating a controlled microenvironment to promote specific biological reactions. They play a vital role in the modern biotechnology industry, providing a stable and controllable condition to accelerate or extend the life cycle of microorganisms, cells and enzymes. This technology has a wide range of applications, covering everything from pharmaceutical production to fermentation production in the food industry, to wastewater treatment and the development and utilization of bioenergy. The core advantage of bioreactors lies in their ability to precisely control biological reaction conditions, making them an indispensable tool for the development of modern biotechnology. By continuously optimizing the design and operating parameters of reactors, scientists and engineers are pushing the field of biological science forward to achieve higher yields, better quality and lower costs.

Basic working principle of bioreactor

Establishment of reaction environment
The bioreactor usually contains a reaction vessel (tank) containing culture medium (containing water, carbon source, nitrogen source, minerals, etc.) and microorganisms, cells or enzymes. In this environment, the organism converts raw materials through metabolic processes to produce target products.

Temperature control
The metabolic activities of microorganisms or cells are very sensitive to temperature. Too high or too low temperature may inhibit their growth or metabolic reactions. Therefore, the bioreactor needs to accurately adjust the temperature of the reaction liquid, usually through a jacketed or internal coil cooling/heating system.

Oxygen supply
In aerobic fermentation, microorganisms or cells need oxygen for metabolism. Oxygen solubility is closely related to the stirring of the reaction liquid and gas flow. Gas (such as air or pure oxygen) is injected into the reactor through an air pipe or a gas distributor, and the bubbles are stirred and mixed by the liquid, so that oxygen is dissolved in the reaction liquid for use by microorganisms or cells.

pH control
Microorganisms or cells will produce acidic or alkaline metabolites (such as organic acids, ammonia, etc.) during growth, which affects the pH value of the culture liquid. The bioreactor is equipped with a pH sensor and an acid-base adjustment system to monitor and adjust the pH value in real time. Maintaining the appropriate pH range by adding acid (such as hydrochloric acid) or alkali (such as sodium hydroxide) ensures the normal growth of organisms.

Agitation and mixing
The bioreactor is equipped with a stirring system (such as impeller, stirring paddle, etc.), whose main function is to evenly mix the reaction liquid, culture medium, microorganisms/cells and oxygen. Agitation can also promote the dissolution of gases, so that dissolved oxygen is fully supplied to microorganisms or cells. Different types of stirring methods (such as mechanical stirring, gas lift stirring) will be selected according to the intensity required for the reaction.

Waste gas emission and pressure control
Due to the metabolic process in the bioreactor, gases (such as CO₂, nitrogen, etc.) are produced. These gases need to be discharged in time to prevent gas accumulation and excessive reactor pressure. The reactor is equipped with an exhaust system to release these waste gases while maintaining internal and external pressure balance.

Online monitoring and control

Types of biological reactions in bioreactors
Aerobic reaction: A process that requires oxygen for metabolism, such as the cultivation of most bacteria, yeast, etc. In this process, microorganisms absorb oxygen to perform respiration and decompose organic matter into carbon dioxide and water.
Anaerobic reaction: A process that does not require oxygen, such as some microorganisms decomposing sugars to produce gases (such as methane, ethanol, etc.) under anaerobic conditions. This reaction is often used in the production of biogas and the synthesis of certain biochemicals.
Cell culture: Used for large-scale cultivation of animal cells or plant cells for the production of vaccines, monoclonal antibodies, recombinant proteins and other biological products.

Key control factors of reactor principle
Dissolved oxygen (DO): It is necessary for the metabolism of microorganisms or cells. It is necessary to ensure sufficient oxygen solubility in the reaction solution.
pH value: It affects the metabolic activity of microorganisms or cells. Too high or too low pH value will inhibit growth or affect product synthesis.
Temperature: Different microorganisms or cells have optimal growth temperatures. Too high or too low pH value will affect their growth and metabolic efficiency.
Culture medium composition: It provides the carbon source, nitrogen source, minerals and other nutrients required by microorganisms or cells.
Reaction time: Different biological reactions have different reaction times. Too short or too long reaction time will affect the final product yield.

Basic components of bioreactors
Reaction vessel The main part, usually made of stainless steel or glass, with a volume ranging from a few liters at laboratory level to thousands of liters at industrial level.
Stirring system: used to mix culture medium, gas (such as oxygen) and microorganisms or cells to ensure uniform reaction. It can be mechanical stirring or airlift stirring.
Temperature control system: Temperature adjustment through jacket or built-in pipes to ensure the stability of the reaction environment.
Gas supply system: Provide oxygen to microorganisms or cells, usually using air or pure oxygen supply, while controlling gas flow.
pH control system: Maintain the pH value of the reaction environment through acid-base adjustment, usually with acid (such as HCl) or alkali (such as NaOH).
Exhaust system: Remove gases or steam generated in the reaction to avoid excessive pressure or accumulation of harmful gases.
Sampling and control system: used to monitor and collect samples in the reaction solution in real time to ensure that various parameters (such as dissolved oxygen, pH, temperature, pressure, etc.) remain within the optimal range.

Classification of bioreactors
By stirring method:Mechanical stirring reactor: stirring the liquid through impeller or stirring paddle, suitable for reactions requiring high shear force.
Gaslift reactor: stirring through the flow of bubbles generated by rising gas, suitable for relatively mild stirring conditions.
By gas supply method:Open reactor: gas and liquid can be exchanged, suitable for fermentation processes with high oxygen demand.
Closed reactor: usually used for cell culture or drug production to avoid external contamination.
By scale:Laboratory bioreactor: capacity ranges from a few liters to tens of liters, usually used for research and development and small-scale production.
Industrial bioreactor: capacity ranges from hundreds of liters to thousands of liters, suitable for large-scale production.
Application areas of bioreactors
Biotechnology:Used for cell culture, protein, vaccine and antibody production.
Food and beverages:Production of fermented foods such as yogurt, beer, soy sauce, vinegar, etc.
Environmental protection:Used for wastewater treatment and sludge treatment, using microorganisms to degrade harmful substances.
Bioenergy:Used for the production of biofuels such as ethanol, biogas, etc.
Cell culture and genetic engineering:Used for large-scale cultivation of cells or microorganisms to produce specific chemicals or genetically engineered products.

Key control parameters
Temperature: Different microorganisms or cells have different temperature requirements, and temperature control is crucial to the reaction effect.
Dissolved oxygen: Especially in aerobic fermentation, adequate oxygen supply is the key to ensure microbial growth and metabolism.
pH: Most microorganisms grow best within a specific pH range, and pH stability is crucial to the fermentation process.
Stirring speed and gas flow: These factors directly affect the gas dissolution efficiency and the uniformity of the culture medium.

Development trend of bioreactors
With the continuous advancement of technology, the design of bioreactors has been continuously optimized:
Automation and digital control: More and more bioreactors use advanced sensors and automated control systems to monitor and adjust various parameters in real time and improve production efficiency.
Single-use (SUS) reactors: Especially in the field of biopharmaceuticals, the use of disposable reactors can avoid the complex steps of cleaning and sterilization, and improve production flexibility and efficiency.
Multistage reactors: In order to improve the yield and quality of products, many industrial applications have begun to use multistage reactors for step-by-step cultivation and reaction.