JPS6361916B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to antifoaming agents in the fermentation industry. Traditionally, in the fermentation industry, especially in deep aerated culture, a large amount of air bubbles are generated and the fermentation container is filled with foam, which reduces the ratio of the medium to the container, increases the cost per unit container, and It has been desired to suppress air bubbles in the fermentation industry because bubbles during fermentation cause the culture medium or the product to flow out of the container, causing disadvantages such as large losses. As bubble suppression methods, physical defoaming methods using heat, pressure, ultrasonic waves, etc., and chemical defoaming methods by adding an antifoaming agent are known. Many antifoaming agents have been known so far. Examples include silicone emulsions, sorbitan fatty acid esters, higher alcohols, animal and vegetable oils, mineral oils such as paraffin, and polyoxyalkylene glycol derivatives. However, in either case, the antifoaming effect is not sufficient, or it has a negative effect on fermentation (for example, inhibiting the growth of microorganisms used in fermentation or the production of products), or the antifoaming effect does not appear quickly. At present, a satisfactory antifoaming agent has not yet been obtained because the antifoaming agent is not effective or its effect does not last for a long time. As a result of extensive research in order to compensate for these shortcomings, the present inventors have completed a new antifoaming agent that overcomes the above-mentioned shortcomings in all respects. That is, the present invention is an antifoaming agent for fermentation that contains as a main component a compound having the general formula shown below. R-O-(C ₂ H ₄ O) _l (C _a H _2a O) _n (C ₂ H ₄ O) _o -A In the formula, R is an alkyl group having 1 to 24 carbon atoms or an alkenyl group, and l is 1 to 10, m is a number of 10 to 80, preferably 10 to 60, n is a number of 0 to 20, preferably 0 to 10, a is an integer of 3 or 4, and both may be mixed in the molecule, The polyoxyethylene portion accounts for 25% by weight or less of the total molecular weight, and A is hydrogen or a fatty acid residue having 10 to 20 carbon atoms. That is, the above compound is a compound obtained by adding ethylene oxide to a monohydric alcohol having 1 to 24 carbon atoms, further adding propylene oxide or butylene oxide, and then adding a block of ethylene oxide if necessary, or the terminal thereof. It is a compound that can be obtained by esterifying a hydroxyl group with a fatty acid having 10 to 20 carbon atoms, and can be obtained by a known general synthesis method. The monohydric alcohol used as the raw material here is
Linear primary alcohols such as methanol, ethanol, butanol, hexanol, caprylic alcohol, behenyl alcohol, lauryl alcohol, myristyl alcohol, cetyl alcohol, oleyl alcohol, or 1 with side chains such as isopropanol, 2-ethylhexanol, oxo synthetic alcohol, etc. alcohol, or mixtures such as coconut oil alcohol and hydrogenated tallow alcohol. The alkylene oxides added to these alcohols must be block additions, and the ethylene oxide moiety must be 25% by weight or less of the total molecular weight. That is, if the ethylene oxide content exceeds 25% by weight, water solubility increases and sufficient antifoaming performance is not exhibited. Moreover, if ethylene oxide is not added, the water dispersibility will be insufficient and the foam-breaking power will be insufficient when the antifoaming agent is added dropwise. When esterifying the terminal hydroxyl group, the number of carbon atoms is 10 or more
The 20 fatty acids include capric acid, lauric acid,
Straight chain fatty acids such as myristic acid, arachidic acid, stearic acid, and oleic acid, side chain fatty acids such as isostearic acid, and hydroxy fatty acids such as hydroxystearic acid are preferably used alone or in mixtures. The antifoaming agent of the present invention has superior antifoaming and foam suppressing power than any of the conventionally known polyoxyalkylene antifoaming agents, and has a significantly lower inhibitory effect on microorganisms. The ethylene oxide chain following the alcohol residue is preferably 1 to 10 moles, particularly 1 to 3 moles, and the ethylene oxide chain following the propylene oxide, butylene oxide, or a mixture thereof is 0 to 20 moles, combined with the ethylene oxide chain. If the amount is 25% by weight or less, preferably 5 to 15% of the total molecular weight, it exhibits foam-breaking power that cannot be achieved with conventional alkylene oxide-derived antifoaming agents. If the propylene oxide chain is short, the foam-breaking power increases, but the foam-inhibiting power decreases. Further, if the length is longer, the foam suppressing power increases, but the foam breaking power decreases. For this reason, in order to maintain a balance between foam-breaking and foam-inhibiting power, alcohol residues must be at least 75% by weight of the total molecular weight.
The number of moles added is 10 to 80 moles. The above-mentioned non-esterified compound itself is an extremely effective antifoaming agent for fermentation, but by esterifying its terminal hydroxyl group with a fatty acid, the length of the propylene oxide chain or butylene oxide chain can be shortened. It can have excellent defoaming performance. In this case, the number of propylene oxide chains or butylene oxide chains can be reduced by 2 to 8 moles. The antifoaming agent of the present invention can be applied to various fermentations, such as yeast cell production, fermentation production of various enzymes such as protease, fermentation production of various nucleic acid-related substances such as inosine fermentation and guanosine fermentation, and L- It can be used in various amino acid fermentations such as glutamic acid, L-lysine fermentation, L-threonine fermentation, and L-proline fermentation. The antifoaming agent of the present invention can be added in a small amount to achieve sufficient effects, and at the same time, even when used in excess,
It can be varied over a wide range due to its low inhibitory effect on the growth of bacterial cells, but in general, adding 0.001 to 1.0% by weight is sufficient to achieve the purpose. In addition, as for the addition method, it has a lower viscosity than conventional alkylene oxide-derived antifoaming agents, so it can be added as a neat solution using a pump.Furthermore, it has strong self-emulsifying properties, so it can be diluted and dispersed in water. It is also possible to use Examples are shown below to explain the antifoaming agent of the present invention and its effects. Example 1 (Yeast fermentation) A Antifoaming effect Culture solution composition Component blending amount (parts by weight) 25% molasses solution 140 Urea 2.25 KH ₂ PO ₄ 1.0 Add water to make the total 400 parts by weight with 1N-HCl.
Adjust PH to 4.5. Add 370 g of the above culture solution to 30 g of seed yeast, put it into a fermentation tank (1 graduated cylinder), and aerate for 10 min. When the foam generated reaches the marked line (1), the defoaming shown in Table 1 A small amount of each agent was added and fermentation was carried out at 30°C for 3 hours. Table 2 shows the minimum amount of antifoaming agent required to suppress the generated foam to below the marked line. The smaller the amount used, the greater the antifoaming effect.

【table】

【table】

[Table] B Foam-breaking effect Same as test A, 30g of seed yeast, 370g of culture solution.
was placed in a graduated cylinder and aerated for 10 minutes. When the foam generated reached the marked line (1), 0.015g of antifoaming agent was added and the time required for the foam top to reach the lowest point. The foam height at the lowest point was measured. The results are shown in Table 3. An antifoaming agent with a short fall time, a low foam height at the lowest point, and a small amount used in Test A is considered to be an antifoaming agent with good foam-breaking properties.

【table】

[Table] Example 2 (L-glutamic acid fermentation) Medium composition for L-glutamic acid fermentation Amount (parts by weight) Glucose 2.0 NH ₄ Cl 0.7 KH ₂ PO ₄ 0.1 MgSO ₄・7H ₂ O 0.05 Add water and mix 100 parts by weight, 0.1N
Adjust the pH to 70 with NaOH and use it as a medium. 50ml of the above medium plus 5μg of biotin
was collected in a 500 ml shaking flask, inoculated with a strain of the genus Micrococus, and cultured with shaking at 30°C for 24 hours to obtain a preculture solution. Next, 50 ml of the above medium was collected into a 500 ml shaking flask, 0.1% and 0.5% of the antifoaming agents shown in Table 1 were added, respectively, 1 ml of the preculture solution was inoculated, and shaking culture was performed at 30° C. for 48 hours. Table 4 shows the production amount of L-glutamic acid.

【table】

[Table] The antifoaming agent of the present invention has a higher production amount of L-glutamic acid than the comparative product, and does not significantly decrease in production compared to the case where no antifoaming agent is added. Further, even if the amount of antifoaming agent added is increased, the amount of decrease in L-glutamic acid production is extremely small. The antifoaming agent of the present invention has an extremely low inhibitory effect on fermentation production and has an excellent antifoaming effect. Example 3 (L-glutamic acid fermentation) The following test was conducted using the same preculture solution and medium as in Example 2. Fermentation tank (capacity 5000ml) with 50 parts of culture medium and 1 preculture part
A portion was taken and cultured for 48 hours at an aeration rate of 3/min and a temperature of 30°C. 400 ml of this culture solution was placed in a graduated cylinder and aerated at 30°C at a rate of 10/min. When the generated foam reached the marked line (1), an antifoaming agent was added little by little and the process was continued for 2 hours. Table 5 shows the minimum amount of antifoaming agent required to suppress the generated foam below the marked line.

【table】

[Table] The antifoaming agent of the present invention also shows excellent antifoaming effects in tests using L-glutamic acid fermentation liquid as the foaming liquid.

Claims (1)

[Claims] 1 General formula R-O-(C ₂ H ₄ O) _l (C _a H _2a O) _n (C ₂ H ₄ O) _o A (wherein R is a carbon atom number of 1 to 24) Alkyl or alkenyl group, l is a number from 1 to 10, m is a number from 10 to 80,
n is a number from 0 to 20, a is a number from 3 or 4, and both may be mixed in the same molecule, and A is a hydrogen atom or a fatty acid residue having 10 to 20 carbon atoms, and the proportion of oxyethylene chains. is less than 25% by weight of the molecule) as an essential component.