Fermentation is the earliest known and utilized by cells in large-scale cell culture techniques. The wide application of fermentation technology in the fields of medicine, light industry, food, agriculture, environmental protection, etc. makes this technology play an increasingly important role in the development of the national economy.
In order to improve the level of fermentation production, the first consideration is the breeding of strains or the construction of genetic engineering. In fact, the optimization of the fermentation process, including engineering problems in the bioreactor, is equally important.
Optimization of Fermentation Environment Conditions Optimization of fermentation environment conditions is the most basic requirement in the fermentation process, and the most important and difficult to grasp technical indicators. The optimal control of temperature, pH, dissolved oxygen, stirring speed, ammonia ion, metal ion, nutrient concentration, etc., varies according to different fermentations. At the same time, microorganisms may have different requirements for environmental conditions at different stages of growth and production of metabolites of interest. Therefore, the temperature, pH value, dissolved oxygen, stirring speed, etc. should be constantly changed in the bioreactor, and the best environmental conditions are always provided to improve the yield of the target product.
In the fermentation amplification experiment, it is generally focused on finding the best medium formula and the best parameters such as temperature, pH value, dissolved oxygen, etc., but the changes in cellular metabolic flux are often neglected. For example, in the measurement and control of dissolved oxygen concentration, the most important oxygen concentration or its critical value is concerned, regardless of the oxygen uptake rate during cell metabolism; when adjusting the pH value with ammonia water, the most important value is concerned. However, it does not pay attention to the dynamic changes in the addition of ammonia and its relationship with the parameters of other fermentation processes, and these changes are very important for cell growth and metabolism.
The mechanism of action of ultrasound is divided into thermal action, cavitation and mechanical mass transfer. Thermal action is a phenomenon in which the energy is continuously absorbed by the medium and the temperature of the medium is raised during the propagation of the ultrasonic wave in the medium, which can be used for sterilization or inactivation of the enzyme. Cavitation is the variation of the average distance of molecules in a liquid as the ultrasonic waves propagate through the medium. Cavitation (cavitation) is formed when it exceeds the critical molecular spacing that maintains the action of the liquid. The vacuole can generate instantaneous high temperature and high pressure accompanied by strong shock wave or ray flow, which is enough to change the cell membrane structure and exchange substances inside and outside the cell. The mechanical mass transfer of the fermenter is that when the ultrasonic wave propagates in the medium, the medium particle can enter the vibration state, accelerate the mass transfer of the fermentation liquid, and improve the reaction speed of the fermentation process.
Ultrasound can be widely used in biological fermentation engineering. Ultrasonic waves of different frequencies and intensities have different effects on the fermentation process, and should be selected according to the specific fermentation process and use conditions.
Increasing the synthesis of the precursor increases the synthesis of the precursor of the target product or directly adds the precursor, which is beneficial to the large accumulation of the target product. For example, in the fermentation of amino acids, the precursor is usually added to the culture of the microorganism to produce amino acids; in the fermentation of arachidonic acid, the synthesis of the precursor is increased by increasing the precursor or enhancing the pathway of sugar metabolism. Both help to increase the production of arachidonic acid.
Based on this, Zhang Yiliang of East China University of Science and Technology put forward the idea of ​​“fermentation engineering with cell metabolic flow analysis and control as the coreâ€. He believes that it is necessary to attach great importance to the phenomenon of changes in the distribution of cellular metabolic fluxes, to study the correlation between the flow of cellular metabolites and the changes in the flow of bioreactors, to attach great importance to the growth and changes of cells, and to make as many actual changes as possible from growth and changes. The analysis of value further establishes the relationship between the cell growth variables and the operational variables and environmental variables of the bioreactor, so as to effectively control the metabolic flow of the cells and optimize the fermentation process.
Fed-batch fermentation technology This technology can effectively reduce the mass transfer efficiency caused by the increase of medium viscosity during fermentation, the degradation of degradants and the feedback inhibition of substrates, and well control the metabolic direction and prolong product synthesis. Period and increase the accumulation of metabolites.
The addition of the required nutrient limit is often used to control auxotrophic mutant strains to maximize the accumulation of metabolites. The use of this fed-batch technique in amino acid fermentation is most common and achieves accurate metabolic regulation.
The application of ultrasound to ultrasound has a strong biological effect. It can be applied to the upper, middle and lower stages of the fermentation process. Its application in the fermentation process can increase the permeability and selectivity of the cell membrane, promote the denaturation or secretion of the enzyme, enhance the cell metabolism process, thereby shortening the fermentation time, improving the biological reaction conditions, and improving the quality and yield of the biological product.
Removal of metabolic end products changes the permeability of the cell membrane, and the end product belonging to the feedback control factor is rapidly and continuously discharged out of the cell, and the final product is not accumulated to a concentration that can cause feedback regulation, that is, feedback control can be prevented.
There are many ways to optimize the fermentation process. They are not isolated but interconnected. In a fermentation, it is often a combination of multiple optimization methods. The purpose is to control the fermentation and produce more and better products according to your own design.
Medical Masks,Medical Scrub Caps,Earloop Face Mask,Face Masks And Caps
Xinxiang Huaxi Sanitary Materials Co., Ltd. , https://www.huaximedical.com