MindMap Gallery Main process parameters of fermentation process
The main process parameters of the fermentation process are to adjust the nutrient matrix concentration of the culture medium. First, the base culture medium must have an appropriate ratio, which is controlled through intermediate feeding, and sterile water is added to the fermentation tank.
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This is a mind map about bacteria, and its main contents include: overview, morphology, types, structure, reproduction, distribution, application, and expansion. The summary is comprehensive and meticulous, suitable as review materials.
This is a mind map about plant asexual reproduction, and its main contents include: concept, spore reproduction, vegetative reproduction, tissue culture, and buds. The summary is comprehensive and meticulous, suitable as review materials.
This is a mind map about the reproductive development of animals, and its main contents include: insects, frogs, birds, sexual reproduction, and asexual reproduction. The summary is comprehensive and meticulous, suitable as review materials.
Main process parameters of fermentation process
Cell concentration
Control Method
To adjust the nutrient matrix concentration of the culture medium, first make the basic culture medium There is an appropriate ratio of nutrients
Controlled by intermediate feeding
Add sterile water to the fermenter
Nutrient matrix
carbon source
Control Method
Industrial fermentation media often use mixed media containing rapid and slow utilization. Carbon source to control bacterial growth and product synthesis
Empirical approach: Determining fermentation according to different metabolic types Process sugar supplement time, sugar supplement amount, sugar supplement method
Kinetic method: control based on kinetic parameters
Nitrogen source
Control Method
Fermentation media are generally selected containing fast and slow utilization mixed nitrogen source
Add nitrogen source during fermentation to control its concentration
Phosphate
Control Method
Use appropriate phosphate concentrations in basal media
Sub-optimal phosphate concentration is often used in antibiotic fermentation (sub-optimal amount: slightly lower than the optimal amount for bacterial growth)
The optimal concentration of phosphate must be combined with the specific local conditions and use The raw materials used were determined experimentally
temperature
Influencing factors
thermogenic factors
biothermal
The heat energy produced by bacteria during their growth and reproduction
The size of biological heat varies with bacterial species and culture medium composition. change with the same
The magnitude of biological heat also varies with culture time. same. The maximum amount of heat released is during the logarithmic growth phase.
The amount of biological heat corresponds to the respiratory intensity of the bacteria Relationship
Stir hot
The stirring between the liquid and the liquid and the equipment caused by the rotation of the agitator The heat generated by the friction between the equipment
Heat dissipation factors
heat of evaporation
After the air enters the fermentation tank and comes into extensive contact with the fermentation liquid, The heat energy required to cause water to evaporate is the heat of evaporation
radiant heat
due to the temperature difference between the outer wall of the tank and the atmosphere Part of the heat in the fermentation liquid can be radiated to the atmosphere through the tank radiation, this part of the heat is radiant heat
Sensible heat
The heat taken away by the exhaust gas when it is discharged due to temperature differences
Fermentation heat = biological heat, stirring heat - evaporation heat - radiant heat - sensible heat
Control Method
The most important choice is temperature
Choose different fermentation temperatures according to different fermentation stages
Adjust the fermentation temperature appropriately according to changes in fermentation conditions
temperature control
In industrial production, a large amount of fermentation chemicals are released during fermentation. Hot, more cooling is needed
Principle: Pour cold water into the jacket or snake tube for control; When the temperature is high, chilled brine is used for circulating cooling. temperature, can quickly reach constant temperature
PH
Influencing factors
The main factors that affect the pH value of fermentation broth are: bacteria genetic characteristics, culture medium components, culture conditions
Fermentation can be inferred from the changes in pH value of the metabolic curve. The progress of various biochemical reactions in the tank and the changes in pH Possible reasons for the exception
Control Method
Determination of fermentation pH
Control different pH ranges according to different stages of the fermentation process range to maximize product output
The optimal pH is determined experimentally
Principle: Adjust the fermentation medium to different starting pH for fermentation. During the fermentation process, the pH is measured and adjusted regularly to maintain the starting point. pH value, observe the growth of the bacteria at that time, and use the growth of the bacteria to reach The maximum pH value is the optimal pH value for bacterial growth
The same method can be used to determine the optimal pH value for product synthesis.
PH control
Adjust the composition of the fermentation medium
The basic formulation of the fermentation medium needs to be considered and tested, Make them have an appropriate ratio to adjust the pH during the fermentation process changes within the appropriate range
Feeding
Add pH buffer to fermentation medium
Change fermentation conditions
Add acid and alkali directly
Dissolved oxygen
Influencing factors
Under certain fermentation conditions, each product fermented Dissolved oxygen concentration changes have their own rules
Early stage of fermentation: bacteria grow and dissolved oxygen appears at a low peak; Product synthesis period: The dissolved oxygen level is relatively stable and will be affected by Effects of feeding and anti-foaming oil
Late stage of fermentation: bacterial cells age and dissolved oxygen gradually increases
abnormal situation
Abnormal decrease in dissolved oxygen
aerobic bacteria
Abnormalities in bacterial metabolism
Failure of certain equipment or changes in process controls
Abnormally elevated dissolved oxygen
When the oxygen supply conditions do not change, the display of oxygen consumption will cause an abnormal increase in dissolved oxygen
Special attention: whether it is contaminated with virulent phages (if it is contaminated with virulent phages: Before the producing bacteria are lysed, respiration is inhibited → dissolved oxygen increases significantly When the bacterial cells rupture, they will completely lose their ability to breathe → dissolved oxygen will rise linearly)
Control Method
Increase oxygen supply
Oxygen supply capacity: Improve the driving force of oxygen delivery and liquid volume oxygen Transfer coefficient KLa
Driving force: ΔC = (C*-CL), mainly affected by C*, And C* is mainly affected by temperature, tank pressure, and properties of the fermentation broth. Sound (difficult to change)
KLa: Increase stirring speed, increase ventilation flow rate, reduce Viscosity, etc.
Control oxygen demand
Control the bacterial concentration at the optimal bacterial concentration
Bacteria can be controlled by controlling the concentration of the nutrient matrix body concentration
CO2
Control Method
Aeration and stirring is a method to control CO2 concentration. Increasing ventilation and stirring speed will help increase CO2 concentration in the fermentation broth. Otherwise it decreases
Use alkali to neutralize the carbonic acid produced by CO2 (CaCO3 cannot be used )
Adjust tank pressure
Control sugar supplements
Foam
Control Method
Bubble control
Adjust the composition of the culture medium and change some fermentation bars or change the fermentation process to control
Mechanical defoaming
Use mechanical strong vibration or pressure changes to burst the foam
Install anti-foam propeller
Antifoaming agent
Defoamers reduce the mechanical strength of the foam liquid film or reduce Low liquid film surface viscosity, or both, makes Foam bursts (antifoaming agents are surfactants)