Application research of polyether defoamer in amino acid fermentation process
1. Introduction
Amino acid fermentation is an important production process in the field of biotechnology, widely used in many industries such as food, medicine, and feed. However, in the fermentation process, due to the metabolic activities of microorganisms and aeration and stirring operations, a large number of foam will inevitably be produced. The presence of foam will not only occupy the effective volume of the fermentation tank, reduce the fermentation efficiency, but also may lead to increased risk of bacterial contamination, affecting the yield and quality of amino acids. The application research of polyether defoamers as a commonly used type of defoamer in amino acid fermentation is of great significance.
2. Overview of Fermentation Process
2.1 Fermentation Temperature
The amino acid fermentation temperature in this study was set at 37 ℃, which is close to human body temperature. This specific temperature is not arbitrarily determined, but has been optimized and screened through numerous rigorous and systematic experiments, repeated testing, comparison, and detailed analysis of various temperature gradients. Among numerous alternative temperatures, 37 ℃ stands out and has been proven to be an extremely suitable key temperature condition for microbial growth and metabolism. At this temperature environment, various enzyme systems involved in amino acid synthesis act as efficient engines that are activated, maintaining a high level of activity and catalyzing amino acid synthesis reactions continuously and stably. At the same time, under the nourishment of this temperature, the growth and reproduction process of microbial cells seems to have stepped onto a high-speed channel, with just the right speed, neither too rapid and causing rapid consumption of nutrients and metabolic imbalance, nor too slow and affecting the efficiency of amino acid synthesis. The ideal growth and reproduction trend of microorganisms is like carefully building a solid and stable foundation for the efficient synthesis of amino acids, effectively promoting the continuous progress of amino acid synthesis reactions along an efficient and orderly track, laying a solid foundation for obtaining considerable amino acid production and high-quality products in the future. It is one of the crucial core elements in the entire amino acid fermentation process.
2.2 Fermentation duration and foam change
The whole fermentation process lasts for 42 hours. About 9 hours after the beginning of fermentation, foam begins to produce, which is mainly because microorganisms secrete some surface active metabolites during the initial growth process, and at the same time, aeration and stirring make the culture liquid fully contact with the air, forming the embryonic form of foam. With the progress of fermentation, the foam reached its peak during 15-21 hours. At this stage, the microbial growth enters the logarithmic phase, and the metabolism is vigorous. The generated surfactant increases. The continuous effect of ventilation volume and agitation intensity also promotes the massive accumulation of foam. However, after 30 hours, as the fermentation gradually entered a stable and declining period, microbial metabolism slowed down and foam gradually decreased.
3. Preparation and addition of defoamers
3.1 Preparation of defoamer:
Polyether defoamer is first diluted with water to a concentration of 3%, and then stored in a dedicated defoamer tank. After this dilution treatment, the flowability and dispersibility of the defoamer were significantly improved, providing great convenience for subsequent precise addition to the fermentation tank, effectively ensuring timely and uniform defoaming during the amino acid fermentation process, and effectively guaranteeing the stability and efficiency of the fermentation process.
3.2 Addition Method:
Throughout the entire fermentation process, a specialized pumping device is used to accurately and directly inject the diluted defoamer into the fermentation tank. The specific time and amount of defoamer addition must be accurately controlled and flexibly adjusted according to the actual situation of foam production in the fermentation process. Only in this way can we achieve the core goal of effectively eliminating foam and avoiding the excessive accumulation of foam from affecting the normal process of fermentation, and at the same time, effectively prevent any form of negative interference or adverse impact on the key links such as microbial growth, metabolism and amino acid synthesis in the fermentation process due to the excessive addition of defoamer or improper addition timing, so as to comprehensively guarantee the stable, efficient and orderly progress of fermentation operations, and lay a solid foundation for the production of high-quality amino acids.
4. Substrate and strain
4.1 Substrate Fermentation:
The substrate contains multiple components, among which glucose is the main carbon source for microbial growth and amino acid synthesis, providing energy and the carbon skeleton required for cell synthesis and metabolism. Total nitrogen is an important source of raw materials for microorganisms to synthesize nitrogen-containing biomolecules such as proteins and nucleic acids. Starch sugar is made from corn and can slowly release glucose to maintain a stable supply of carbon source during fermentation. In addition, it also contains other nutrients such as vitamins, minerals, etc., which play an indispensable role in maintaining the normal growth and metabolic functions of microorganisms.
4.2
Different types of amino acid production depend on specific bacterial strains to achieve. As for the production of lysine, lysine producing bacteria are undoubtedly the core strains. Under specific fermentation conditions that meet its growth and metabolic needs, lysine bacteria can fully absorb and efficiently utilize various nutrients contained in substrates. With its unique and complex metabolic system, it systematically undergoes a series of fine and interrelated metabolic steps and biochemical reaction pathways, gradually transforming and synthesizing substances in substrates into the target product lysine, providing a solid and reliable biological basis and key technical support for the industrial production of lysine.
5. Application comparison of polyether defoamers
5.1
When applying the first polyether defoamer in lysine fermentation production, it was found that its unit consumption was 3.2 Kg/t, exceeding the requirement of using less than 3.0 Kg/t of defoamer per ton of lysine produced. Such a high unit consumption situation is highly likely to significantly increase production costs, and at the same time, due to excessive addition of defoamers, it is highly likely to exert a certain degree of inhibitory effect on the entire fermentation process. Excessive defoamer components may interfere with the normal permeability of microbial cell membranes within a specific range, disrupt the balance of substance exchange and information transmission inside and outside microbial cells, and thus interfere with and hinder various physiological metabolic activities of microorganisms. Ultimately, it will have a negative impact on the synthesis yield and product quality of lysine, greatly reducing the efficiency and quality of fermentation production.
5.2
Theunit consumption of the second polyether defoamer during the same lysine fermentation process is 2.4 Kg/t, which is lower than the required amount. Compared with the first defoamer, its defoamer dosage has been reduced by 15%. This data fully demonstrates the superior performance of the second defoamer in terms of defoaming effect presentation and precise control of dosage. It can not only accurately and efficiently control foam in the fermentation process, maintain the amount of foam at an appropriate level, minimize the adverse interference of foam on the fermentation operation, but also effectively avoid a series of negative problems caused by the excessive use of defoamer, such as affecting the microbial metabolic environment, impeding the lysine synthesis process and so on, thus providing strong support for the improvement of lysine fermentation efficiency and the optimization of product quality. From an economic cost perspective, the consumption of defoamers has been reduced, directly reducing production costs; From a process perspective, it ensures the stability and continuity of the fermentation process, reduces the risk of process fluctuations caused by defoamers, and has outstanding advantages in both economic and process perspectives. It provides a more valuable defoamer application solution for the refined and efficient operation of the amino acid fermentation industry.
conclusion
Polyether defoamers play a crucial role in the amino acid fermentation process. Through the study of fermentation process parameters, preparation and addition of defoamers, substrate strains, and the application effects of different defoamers, it is known that the rational selection of polyether defoamers is crucial for improving the economic benefits and product quality of amino acid fermentation. In this study, the second polyether defoamer demonstrated greater potential for application with its lower unit consumption and good defoaming effect. Future research can further explore the mechanism of action of polyether defoamers, optimize their formulations and application conditions, in order to better meet the evolving needs of the amino acid fermentation industry.
