High Purity L-threonine Price,Fermentation Preparation

In the process of fermentative production of L-threonine, the following fermentation conditions need to be strictly controlled to ensure the smooth progress of fermentation and improve the yield and quality of L-threonine:

1. Composition of Culture Medium

·Carbon Source: Common carbon sources include glucose, sucrose, starch, etc. The carbon source not only provides energy for the growth of microorganisms but is also an important raw material for the synthesis of L-threonine. It is necessary to accurately control the type and concentration of the carbon source according to the characteristics of the bacterial strain and the fermentation stage. For example, in the early stage of fermentation, an appropriate amount of glucose can promote the rapid growth and reproduction of the bacterial cells; in the acid production period, it may be necessary to adjust the supply rate and proportion of the carbon source to maintain the metabolic activity of the bacterial cells and the synthesis of L-threonine.

·Nitrogen Source: The nitrogen source is a key element for the synthesis of amino acids and includes organic nitrogen sources (such as peptone, yeast powder, corn steep liquor, etc.) and inorganic nitrogen sources (such as ammonium sulfate, urea, etc.). A reasonable combination of the proportion of organic and inorganic nitrogen sources can not only meet the nitrogen demand for the growth of the bacterial cells but also promote the synthesis of L-threonine. Generally speaking, an appropriate amount of organic nitrogen source can provide rich growth factors, which is beneficial to the growth and metabolic regulation of the bacterial cells.

·Inorganic Salts: Such as phosphates, magnesium salts, iron salts, manganese salts, etc. These inorganic salts play an important role in the metabolic process of the bacterial cells, such as participating in energy metabolism, maintaining cell osmotic pressure, activating enzyme activity, etc. Different inorganic salts have different effects on the synthesis of L-threonine, and their concentrations need to be accurately controlled. For example, an appropriate amount of phosphate can promote sugar metabolism and amino acid synthesis, but too high a phosphate concentration may inhibit the synthesis of L-threonine.

·Growth Factors: Some microorganisms require specific growth factors, such as vitamins, amino acids, etc., in the process of synthesizing L-threonine. Adding an appropriate amount of growth factors can promote the growth and metabolism of the bacterial cells and increase its yield. For example, biotin is an essential growth factor for the growth of some L-threonine-producing strains. An appropriate amount of biotin can enhance the metabolic activity of the bacterial cells and promote its synthesis.

2. Temperature: Temperature has a significant impact on the growth and metabolism of microorganisms. Different bacterial strains have their optimal growth temperature and acid production temperature. Generally speaking, the temperature range for the fermentation production of L-threonine is between 30°C and 37°C. In the early stage of fermentation, appropriately increasing the temperature can promote the growth and reproduction of the bacterial cells; in the acid production period, it may be necessary to adjust the temperature to a level suitable for the synthesis of L-threonine to increase the yield. Too high or too low a temperature will affect the enzyme activity and metabolic pathway of the bacterial cells, resulting in a decrease in its yield.

3. pH Value: The pH value of the fermentation broth will affect the growth and metabolism of microorganisms and the synthesis of L-threonine. During the L-threonine fermentation process, the pH value is generally controlled between 6.5 and 8.0. During the fermentation process, the metabolism of microorganisms will produce acidic or alkaline substances, causing the pH value to change. Therefore, it is necessary to monitor and adjust the pH value in real time. The stability of the pH value can be maintained by adding acids (such as sulfuric acid) or bases (such as sodium hydroxide). An appropriate pH value is helpful to maintain the normal metabolism and enzyme activity of the bacterial cells and promote the synthesis of L-threonine.

4. Dissolved Oxygen: The fermentation of L-threonine is usually an aerobic fermentation, and the concentration of dissolved oxygen is crucial for the growth of the bacterial cells and its synthesis. During the fermentation process, it is necessary to provide sufficient dissolved oxygen through aeration and agitation to meet the respiration and metabolic needs of the bacterial cells. If the dissolved oxygen concentration is too low, the growth of the bacterial cells will be inhibited and the synthesis of L-threonine will decrease; if the dissolved oxygen concentration is too high, it may increase the production cost and may also have an adverse effect on the metabolism of the bacterial cells. Therefore, it is necessary to accurately control the concentration of dissolved oxygen according to the fermentation process and the oxygen consumption of the bacterial cells.

5. Fermentation Time: The control of fermentation time directly affects the yield and quality of L-threonine. In the early stage of fermentation, the bacterial cells mainly grow and reproduce, and its synthesis is relatively small; as the fermentation progresses, the bacterial cells enter the acid production period, and the synthesis of L-threonine gradually increases; when the fermentation reaches a certain time, the metabolic activity of the bacterial cells may decline, and its synthesis will also slow down, and even the product may be degraded. Therefore, it is necessary to determine the optimal fermentation time by monitoring various indicators in the fermentation process (such as bacterial cell concentration, L-threonine concentration, sugar consumption, etc.) to obtain the highest yield and quality of L - threonine.

6. Foam Control: During the fermentation process, due to the influence of aeration, agitation and the composition of the culture medium, a large amount of foam may be produced. Excessive foam will affect the aeration effect, resulting in insufficient dissolved oxygen. At the same time, it may also cause the overflow of the fermentation broth, increasing the risk of contamination. Therefore, effective foam control measures need to be taken, such as adding defoamers, adjusting aeration and agitation conditions, etc., to maintain the stable progress of the fermentation process.