阅读说明：本技术 一种生物发酵生产长链二元酸的方法 (Method for producing long-chain dicarboxylic acid by biological fermentation ) 是由 王邵冰 修德恒 郭启健 于 2021-03-17 设计创作，主要内容包括：本发明提供一种生物发酵生产长链二元酸的方法,其采用热带假丝酵母或维斯假丝酵母作为发酵微生物,包括下述步骤：1)采用两级种子罐对微生物进行培养,其中一级种子罐培养后菌体生长密度(OD620)大于0.5；2)二级种子罐培养结束后将菌液接入到发酵罐中进行发酵,发酵期间pH控制在6.8-7.1范围内。本发明的新方法发酵周期短,烷烃添加量大,产酸高,转化率高,符合节能减排、降低成本的生产要求。(The invention provides a method for producing long-chain dicarboxylic acid by biological fermentation, which adopts candida tropicalis or candida weissensis as fermentation microorganisms and comprises the following steps: 1) culturing microorganisms by adopting a two-stage seeding tank, wherein the growth density (OD620) of thalli cultured in the one-stage seeding tank is more than 0.5; 2) and after the secondary seeding tank is cultured, inoculating the bacterial liquid into a fermentation tank for fermentation, wherein the pH value is controlled within the range of 6.8-7.1 during the fermentation. The novel method disclosed by the invention is short in fermentation period, large in alkane addition, high in acid production and high in conversion rate, and meets the production requirements of energy conservation, emission reduction and cost reduction.)

1. A method for producing long-chain dibasic acid by biological fermentation, which adopts Candida tropicalis or Candida weissensis as fermentation microorganisms, comprises the following steps:

1) culturing microorganisms by adopting a two-stage seeding tank, wherein the growth density (OD620) of thalli cultured in the one-stage seeding tank is more than 0.5;

2) and after the secondary seeding tank is cultured, inoculating the bacterial liquid into a fermentation tank for fermentation, wherein the pH value is controlled within the range of 6.8-7.1 during the fermentation.

2. The method for biofermentation production of long chain dibasic acids in accordance with claim 1, wherein the primary seedtank is subjected to the following processes: alkali water boiling tank: the pH value is approximately equal to 12, the temperature is 120 ℃, and the time is 4 h; air elimination: 130 ℃ for 1 h; actual elimination: properly adjusting the pH value before sterilization to ensure that the pH value before planting is within the range of 6.7-7.0; the temperature is 121-³(ii) a After the actual digestion, quickly cooling, and inoculating and culturing when the temperature is reduced to 30 +/-0.5 ℃.

3. The method for producing a long-chain dicarboxylic acid by biofermentation according to claim 1, wherein the primary culturing process is controlled as follows: (1) normally culturing in the early stage, and when the dissolved oxygen is close to 40%, improving the air quantity, ensuring that the dissolved oxygen is kept between 40 and 50 percent, and gradually improving the air quantity; (2) when the growth density (OD620) of the thalli is more than 0.5, the bacteria liquid dissolves oxygen, the pH rebounds, and the first-stage culture is finished.

4. The method for biofermentation production of long chain dibasic acids in accordance with claim 1, wherein the secondary seed tank is subjected to the following processes: alkali water boiling tank: the pH value is approximately equal to 12, the temperature is 120 ℃, and the time is 4 h; air elimination: 130 ℃ for 1 h; capacity determination is carried out for 17.5t before actual elimination: properly adjusting the pH value before sterilization to ensure that the pH value before planting is within the range of 6.7-7.0; the temperature is 121-; after the actual digestion is finished, quickly cooling, and inoculating and culturing when the temperature is reduced to 30 +/-0.5 ℃; wherein, when the carbon source is glucose, the volume is 1.5t, the volume is 16t, the temperature is 113-.

5. The method for producing a long-chain dicarboxylic acid by biofermentation according to claim 1, wherein the secondary culturing process is controlled as follows: (1) normally culturing in the early stage, and when the dissolved oxygen is close to 40%, improving the air quantity, ensuring that the dissolved oxygen is kept between 40 and 50 percent, and gradually improving the air quantity; (2) and (5) bacteria liquid dissolved oxygen, pH rebounding and finishing secondary culture.

6. The process for producing a long-chain dicarboxylic acid by biofermentation according to claim 1, wherein the bed material water and the carbon source are continuously consumed, the nitrogen source is consumed, and the mixture is pressurized into the fermentation tank after the consumption.

7. The method for producing long-chain dicarboxylic acid by biofermentation according to claim 1, wherein the secondary carbon source is supplemented in a fed-batch manner in the fermentation process, and the process is finished before the alkane raw material is supplemented; after the secondary carbon source is supplemented, adjusting the pH to 6.9, and supplementing alkane raw materials: the interval of the first three times is 6 hours, 3.5t of alkane raw material is supplemented every time, then 3t of alkane raw material is supplemented according to residual hydrocarbon and less than 4%, and dissolved oxygen is controlled to be 40% -50% during the process of supplementing to fermentation.

8. The method for producing long-chain dicarboxylic acid by biofermentation according to claim 7, wherein the secondary carbon source is glucose or sucrose.

9. The method for producing long-chain dicarboxylic acid by biofermentation according to claim 1, wherein the pH is controlled to be reduced to 6.5 at the end of fermentation by considering the addition amount of alkane according to the activity of the thallus in the later stage of fermentation.

10. A long chain dibasic acid produced by the method of any one of claims 1 to 9.

Technical Field

The invention relates to a method for producing long-chain dicarboxylic acid by biological fermentation.

Background

The Long chain dicarboxylic acids (Long chain dicarboxylic acids) refer to aliphatic dicarboxylic acids (DCn for short) with 9 or more carbon atoms in the carbon chain, and include saturated and unsaturated dicarboxylic acids, and are fine chemical products with important and wide industrial application, and important raw materials for synthesizing high-grade spices, high-performance engineering plastics, high-temperature dielectrics, high-grade hot melt adhesives, cold-resistant plasticizers, high-grade lubricating oils, high-grade paints, coatings and the like in the chemical industry.

In general, the long-chain dicarboxylic acid can be produced by chemical synthesis or biological fermentation. The chemical synthesis method has long synthesis route and strict reaction conditions, needs to be carried out under the conditions of high temperature and high pressure, and has strict requirements on the catalyst, so that on an industrial scale, the long-chain dicarboxylic acid synthesized by the chemical method has fewer varieties, and only a few varieties such as twelve carbon long-chain dicarboxylic acid are available. The biological fermentation method takes long-chain alkane as a substrate, and obtains long-chain dibasic acid through microbial fermentation conversion; the production process is carried out under the conditions of normal temperature and normal pressure, and a plurality of long-chain dibasic acids such as C9-C18 can be produced in a large scale. Thus, the advantages of the biofermentation production of long chain diacids over the chemical synthesis are self evident.

At present, a certain research foundation exists for producing long-chain dicarboxylic acid by a biological fermentation method. However, in the existing production process, the density of thalli generated in the microbial inoculation culture process is low, sufficient active thalli cannot be provided for the fermentation process, the pH needs to be continuously adjusted according to the situation in the fermentation process, and the pH undergoes the change of acidity-neutrality-alkalinity.

The problems of long fermentation period (generally 180-190 hours), low acid production rate, low conversion rate and the like commonly existing in the existing production process are solved.

Disclosure of Invention

In order to solve the problems of long fermentation time, low efficiency and low acid production rate of the process for producing the long-chain dibasic acid by a biological method in the prior art, the invention provides a novel method for producing the long-chain dibasic acid by biological fermentation. The novel method disclosed by the invention is short in fermentation period, large in alkane addition, high in acid production and high in conversion rate, and meets the production requirements of energy conservation, emission reduction and cost reduction.

The method for producing the long-chain dicarboxylic acid by biological fermentation, which adopts candida tropicalis or candida weissensis as the fermentation microorganism, comprises the following steps:

1) culturing microorganisms by adopting a two-stage seeding tank, wherein the growth density (OD620) of thalli cultured in the one-stage seeding tank is more than 0.5;

2) and after the secondary seeding tank is cultured, inoculating the bacterial liquid into a fermentation tank for fermentation, wherein the pH value is controlled within the range of 6.8-7.1 during the fermentation.

In the method for producing the long-chain dicarboxylic acid by biological fermentation, the first-stage seed tank is preferably subjected to the following processes: alkali water boiling tank: the pH value is approximately equal to 12, the temperature is 120 ℃, and the time is 4 h; air elimination: 130 ℃ for 1 h; actual elimination: properly adjusting the pH value before sterilization to ensure that the pH value before planting is within the range of 6.7-7.0; the temperature is 121-³(ii) a After the actual digestion, quickly cooling, and inoculating and culturing when the temperature is reduced to 30 +/-0.5 ℃.

The method for producing the long-chain dicarboxylic acid by biological fermentation preferably comprises the following first-stage culture procedures: (1) normally culturing in the early stage, and when the dissolved oxygen is close to 40%, improving the air quantity, ensuring that the dissolved oxygen is kept between 40 and 50 percent, and gradually improving the air quantity; (2) when the growth density (OD620) of the thalli is more than 0.5, the bacteria liquid dissolves oxygen, the pH rebounds, and the first-stage culture is finished.

In the method for producing the long-chain dicarboxylic acid by biological fermentation, the secondary seed tank is preferably subjected to the following processes: alkali water boiling tank: the pH value is approximately equal to 12, the temperature is 120 ℃, and the time is 4 h; air elimination: 130 ℃ for 1 h; capacity determination is carried out for 17.5t before actual elimination: properly adjusting the pH value before sterilization to ensure that the pH value before planting is within the range of 6.7-7.0; the temperature is 121-; after the actual digestion is finished, quickly cooling, and inoculating and culturing when the temperature is reduced to 30 +/-0.5 ℃; wherein, when the carbon source is glucose, the volume is 1.5t, the volume is 16t, the temperature is 113-.

In the method for producing the long-chain dicarboxylic acid by biological fermentation, the preferable secondary culture process is controlled as follows: (1) normally culturing in the early stage, and when the dissolved oxygen is close to 40%, improving the air quantity, ensuring that the dissolved oxygen is kept between 40 and 50 percent, and gradually improving the air quantity; (2) and (5) bacteria liquid dissolved oxygen, PH rebound and secondary culture ending.

In the method for producing the long-chain dibasic acid by biological fermentation, the bottom material water and the carbon source are preferably continuously consumed, the nitrogen source is consumed, and the nitrogen source is pressed into a fermentation tank after being consumed.

In the method for producing the long-chain dicarboxylic acid by biological fermentation, the secondary carbon source is supplemented in a fed-batch mode in the preferable fermentation process, and the process is finished before the alkane raw material is supplemented; after the secondary carbon source is supplemented, adjusting the pH to 6.9, and supplementing alkane raw materials: the interval of the first three times is 6 hours, 3.5t of alkane raw material is supplemented every time, then 3t of alkane raw material is supplemented according to residual hydrocarbon and less than 4%, and dissolved oxygen is controlled to be 40% -50% during the process of supplementing to fermentation.

In the method for producing the long-chain dicarboxylic acid by biological fermentation, the secondary carbon source is preferably glucose or sucrose.

In the method for producing the long-chain dicarboxylic acid by biological fermentation, the pH is preferably controlled to be reduced to 6.5 at the end of fermentation by considering the addition amount of alkane according to the activity of thalli in the later stage of fermentation.

The invention carries out technical innovation from the aspect of microbial culture and fermentation process, adopts a special microbial culture process, increases the bacterial mass, enhances the bacterial activity, controls the pH to be 4.5 after the pH is reduced to 4.5 before the supplement of a secondary carbon source is finished, controls the pH in a neutral environment (pH6.8-7.1) in the fermentation process, and obtains very obvious excellent effects: the fermentation period is shortened from 190 hours to 150 hours, and the addition of alkane is increased from 28t to 36-37t, so that the acid production rate and the conversion rate are both greatly increased.

Detailed Description

The invention aims to provide a method for producing long-chain dibasic acid by biological fermentation, which has the advantages of short fermentation period, large alkane adding amount, high acid production and high conversion rate.

In order to obtain the long-chain dibasic acid with high yield, and the great thallus amount and the strong thallus activity obtained in the microbial culture process are very important, the invention adopts two-stage seed tanks to culture the microbes, and controls the thallus growth density (OD620) to be more than 0.5 after the cultivation in the one-stage seed tank, compared with the prior art, the invention obtains obvious improvement on the aspects of the thallus amount and the thallus activity.

The method for producing the long-chain dicarboxylic acid by biological fermentation comprises the following steps of: alkali water boiling tank: the pH value is approximately equal to 12, the temperature is 120 ℃, and the time is 4 h; air elimination: 130 ℃ for 1 h; actual elimination: the pH is properly adjusted before sterilization so that the pH before seeding is within the range of 6.7-7.0. The temperature is 121 ℃ and 123 ℃, the temperature is kept for 30 minutes, and the mixture is completely consumedThe back volume is 1.4-1.6m³(ii) a After the actual digestion, quickly cooling, and inoculating and culturing when the temperature is reduced to 30 +/-0.5 ℃.

In the first-stage culture process, performing normal culture in an early stage, and increasing the air volume when the dissolved oxygen is close to 40%, so as to ensure that the dissolved oxygen is kept between 40% and 50%, and the air volume is gradually increased; when the growth density (OD620) of the thalli is more than 0.5, the bacteria liquid dissolves oxygen, the pH rebounds, and the first-stage culture is finished.

The secondary seed tank was subjected to the following process: alkali water boiling tank: the pH value is approximately equal to 12, the temperature is 120 ℃, and the time is 4 h; air elimination: 130 ℃ for 1 h; capacity determination is carried out for 17.5t before actual elimination: the pH is properly adjusted before sterilization so that the pH before seeding is within the range of 6.7-7.0. The temperature is 121-; after the actual digestion, quickly cooling, and inoculating and culturing when the temperature is reduced to 30 +/-0.5 ℃. Wherein, when the carbon source is glucose, the volume is 1.5t, the volume is 16t, the temperature is 113-.

The secondary culture process is controlled as follows: normally culturing in the early stage, and when the dissolved oxygen is close to 40%, improving the air quantity, ensuring that the dissolved oxygen is kept between 40 and 50 percent, and gradually improving the air quantity; and (5) bacteria liquid dissolved oxygen, pH rebounding and finishing secondary culture.

And after the secondary seed tank culture is finished, inoculating the bacterial liquid into a fermentation tank for fermentation. The pH of the bacterial liquid in the fermentation process is a comprehensive index of the metabolic activity of the thalli under certain environmental conditions, and has great influence on the growth of the thalli and the product accumulation. In the existing fermentation process, the pH needs to be continuously adjusted according to the conditions in the fermentation process, and the pH undergoes acidic-neutral-alkaline change, and a great deal of experiments show that the pH is kept constant in a narrow range to achieve high growth rate and optimal product formation, so that the long-chain dibasic acid with high yield is obtained. The pH of the fermentation is controlled to be constant within the range of 6.8-7.1 during the fermentation, and the pH is preferably 6.9.

According to the method for producing the long-chain dicarboxylic acid by biological fermentation, a fed-batch mode can be adopted to supplement secondary carbon sources such as glucose or sucrose in the fermentation process, and before the supplement of the secondary carbon sources is finished, the pH is controlled to be 4.5 after being reduced to 4.5; the supplement of the secondary carbon source is finished before the supplement of the alkane raw material; after the secondary carbon source is supplemented, adjusting the pH value to 6.8-7.1, and supplementing alkane raw materials: the interval of the first three times is 6 hours, 3.5t of alkane raw material is supplemented every time, then 3t of alkane raw material is supplemented according to residual hydrocarbon and less than 4%, and dissolved oxygen is controlled to be 40% -50% during the process of supplementing to fermentation.

By improving the fermentation process, the addition amount of alkane can be increased from about 28t to 36-37t, and the acid production rate and the conversion rate are both greatly improved.

In order to better illustrate the present invention, the technical solutions in the embodiments of the present invention are clearly and completely described below with reference to the embodiments of the present invention.

Example 1

The method for producing the long-chain dicarboxylic acid by biological fermentation comprises the following steps:

(1) first-level seeding tank culture: alkali water boiling tank: the pH value is approximately equal to 12, the temperature is 120 ℃, and the time is 4 h; air elimination: 130 ℃ for 1 h; actual elimination: the pH is properly adjusted before sterilization so that the pH before seeding is within the range of 6.7-7.0. The temperature is 121-³(ii) a After the actual digestion is finished, the temperature is rapidly reduced, and candida tropicalis is adopted for inoculation and culture when the temperature is reduced to 30 +/-0.5 ℃.

In the first-stage culture process, performing normal culture in an early stage, and increasing the air volume when the dissolved oxygen is close to 40%, so as to ensure that the dissolved oxygen is kept between 40% and 50%, and the air volume is gradually increased; when the thallus growth density (OD620) is 0.540, the bacteria solution dissolves oxygen, the pH rebounds, and the first-stage culture is finished.

(2) Secondary seeding tank culture: alkali water boiling tank: the pH value is approximately equal to 12, the temperature is 120 ℃, and the time is 4 h; air elimination: 130 ℃ for 1 h; capacity determination is carried out for 17.5t before actual elimination: the pH is properly adjusted before sterilization so that the pH before seeding is within the range of 6.7-7.0. The temperature is 121-; and (5) after the actual digestion is finished, quickly cooling. Wherein, when the carbon source is glucose, the volume is 1.5t, the volume is 16t, the temperature is 113-.

The secondary culture process is controlled as follows: normally culturing in the early stage, and when the dissolved oxygen is close to 40%, improving the air quantity, ensuring that the dissolved oxygen is kept between 40 and 50 percent, and gradually improving the air quantity; and (5) bacteria liquid dissolved oxygen, PH rebound and secondary culture ending.

(3) Fermentation in a fermentation tank: continuously eliminating bottom material water and carbon source, 50 + -5 t after eliminating, completely eliminating nitrogen source, and pressing into fermentation tank after eliminating.

And (3) feeding control parameters: a secondary carbon source is required to be added, the secondary carbon source adopts a fed-batch mode, and before the secondary carbon source is supplemented, the pH is controlled to be 4.5 after being reduced to 4.5; the supplement of the secondary carbon source is finished before the supplement of the alkane raw material; after the secondary carbon source is supplemented, adjusting the pH to 7.1, and supplementing alkane raw materials: the interval of the first three times is 6 hours, 3.5t of alkane raw material is supplemented every time, then 3t of alkane raw material is supplemented according to residual hydrocarbon and less than 4%, and dissolved oxygen is controlled to be 40% -50% during the process of supplementing to fermentation.

The fermentation period is 158 hours, the acid production is 20.8 percent, the alkane addition is 36.1t, and the weight conversion rate of the alkane to the dibasic acid is 81.18 percent.

Example 2

The method for producing the long-chain dicarboxylic acid by biological fermentation comprises the following steps:

(1) first-level seeding tank culture: alkali water boiling tank: the pH value is approximately equal to 12, the temperature is 120 ℃, and the time is 4 h; air elimination: 130 ℃ for 1 h; actual elimination: the pH is properly adjusted before sterilization so that the pH before seeding is within the range of 6.7-7.0. The temperature is 121-³(ii) a After the actual digestion is finished, the temperature is rapidly reduced, and candida tropicalis is adopted for inoculation and culture when the temperature is reduced to 30 +/-0.5 ℃.

In the first-stage culture process, performing normal culture in an early stage, and increasing the air volume when the dissolved oxygen is close to 40%, so as to ensure that the dissolved oxygen is kept between 40% and 50%, and the air volume is gradually increased; when the growth density (OD620) of the thalli is 0.817, the bacteria liquid dissolves oxygen, rebounds pH, and finishes the first-stage culture.

(2) Secondary seeding tank culture: alkali water boiling tank: the pH value is approximately equal to 12, the temperature is 120 ℃, and the time is 4 h; air elimination: 130 ℃ for 1 h; capacity determination is carried out for 17.5t before actual elimination: the pH is properly adjusted before sterilization so that the pH before seeding is within the range of 6.7-7.0. The temperature is 121-; and (5) after the actual digestion is finished, quickly cooling. Wherein, when the carbon source is glucose, the volume is 1.5t, the volume is 16t, the temperature is 113-.

The secondary culture process is controlled as follows: normally culturing in the early stage, and when the dissolved oxygen is close to 40%, improving the air quantity, ensuring that the dissolved oxygen is kept between 40 and 50 percent, and gradually improving the air quantity; and (5) bacteria liquid dissolved oxygen, PH rebound and secondary culture ending.

(3) Fermentation in a fermentation tank: continuously eliminating bottom material water and carbon source, 50 + -5 t after eliminating, completely eliminating nitrogen source, and pressing into fermentation tank after eliminating.

And (3) feeding control parameters: a secondary carbon source is required to be added, the secondary carbon source adopts a fed-batch mode, and before the secondary carbon source is supplemented, the pH is controlled to be 4.5 after being reduced to 4.5; the supplement of the secondary carbon source is finished before the supplement of the alkane raw material; after the secondary carbon source is supplemented, adjusting the pH to 6.9, and supplementing alkane raw materials: the interval of the first three times is 6 hours, 3.5t of alkane raw material is supplemented every time, then 3t of alkane raw material is supplemented according to residual hydrocarbon and less than 4%, and dissolved oxygen is controlled to be 40% -50% during the process of supplementing to fermentation.

The fermentation period is 156 hours, the acid production is 24.2 percent, the alkane addition is 36.6t, and the weight conversion rate of the alkane to the dibasic acid is 91.96 percent.

Comparative example 1

In the method for producing the long-chain dicarboxylic acid by the biological fermentation in the comparative example 1, only a first-stage seeding tank is adopted to inoculate and culture the candida tropicalis, when the growth density (OD620) of thalli is 0.498, the dissolved oxygen and the pH of a bacterial liquid rebound, and after the culture is finished, fermentation tank fermentation is carried out; except for this, a long chain dibasic acid was prepared in the same manner as in example 1.

The fermentation period is 192 hours, the acid yield is 17.2 percent, the alkane adding amount is 27.2t, and the weight conversion rate of the alkane to the dibasic acid is 68.39 percent.

Comparative example 2

In the method for producing the long-chain dicarboxylic acid by biological fermentation of the comparative example 2, in the fermentation process, after the secondary carbon source is supplemented, the pH is adjusted to 7.5; except for this, a long chain dibasic acid was prepared in the same manner as in example 2.

The fermentation period is 185 hours, the acid yield is 18.5 percent, the alkane addition is 27.6t, and the weight conversion rate of the alkane to the dibasic acid is 73.64 percent.

The following table shows the parameters of the examples and comparative examples:

	fermentation period (hr)	Acid yield (%)	Amount of alkane added (t)	Alkane conversion (%)
					Example 1	158	20.8％	36.1	81.18％
Example 2	156	24.2％	36.6	91.96％
					Comparative example 1	192	17.2％	27.2	68.39％
Comparative example 2	185	18.5％	27.6	73.64％

By the method for preparing the binary acid in the embodiments 1 and 2, the fermentation period can be shortened from the existing 190-150-160 h, so that the energy consumption is greatly reduced, and the production cost is reduced; the acid yield is improved to more than 20 percent from about 10 percent in the prior art, the weight conversion rate of the alkane to the dibasic acid is improved to more than 80 percent from 60 to 70 percent in the prior art, particularly, the conversion rate of the preparation method of the embodiment 2 is up to 91 percent, and the economic benefit is greatly increased.

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention disclosed herein should be covered within the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.