Process for producing butyric acid by using bagasse hydrolysate through clostridium tyrobutyricum fermentation

Abstract

The invention discloses a process for producing butyric acid by using bagasse hydrolysate through clostridium tyrobutyricum fermentation. The process comprises the following steps of: inoculating clostridium tyrobutyricum into a seed medium to obtain first-grade seeds; inoculating the first-grade seeds into a seed medium to obtain second-grade seeds serving as fermentation parent seeds; and inoculating the fermentation parent seeds into a pre-fermentation tank, performing amplification culture, pumping a culture solution into a fibrous-bed bioreactor, maintaining circulation, and when free thallus concentration is reduced to 1.0-3.0g / L, changing the culture solution into a bagasse hydrolysate fermentation medium for batch fermentation, fed-batch fermentation or repeated-batch fermentationto obtain the butyric acid. The process is simple; the bagasse hydrolysate is taken as a carbon source, and the fibrous-bed bioreactor is used for immobilized fermentation; bagasse and other agricultural wastes can be recycled; the cost of producing the butyric acid by a fermentation method is reduced; the fermentation productivity and yield of the butyric acid are improved; meanwhile, repeated inoculation can be eliminated, continuous long-term stable operation is realized and the process is suitable for industrial scale-up.

Description

technical field

[0001] The invention relates to a process for producing butyric acid, in particular to a process for producing butyric acid by using Clostridium tyrobutyricum to ferment bagasse hydrolyzate, and belongs to the technical field of organic acid fermentation. Background technique

[0002] N-butyric acid (Butyric acid, hereinafter referred to as butyric acid), also known as butyric acid, has four carbon atoms in its molecule and is a short-chain saturated fatty acid connected in a straight-chain manner. It has a pungent odor, and very dilute solutions also have sweaty odor. taste. Butyric acid often exists in nature in the form of ester or free state. Butyric acid is a versatile fine chemical widely used in food, chemical and pharmaceutical industries. It is used in the preparation of candy and beverage flavoring agents in the food industry, and in the preparation of fruit flavors in the spice industry; cellulose butyrate is superior to cellulose acetate in term...

Examples

Embodiment 1

[0029] What present embodiment provides is the technology that carries out fiber bed immobilization Clostridium tyrobutyricum batch fermentation butyric acid with bagasse hydrolyzate as carbon source, and the steps are as follows:

[0030] 1) Dip the Clostridium tyrobutyricum bacteria liquid with an inoculation needle, streak on the enhanced medium plate containing 50 mg / mL sodium butyrate, and culture at 37 °C for 72 hours. The classification and naming of Clostridium tyrobutyricum (No. ATCC 25755): the Chinese name is Clostridium tyrobutyricum, and the Latin literary name is Clostridium tyrobutyricum , Clostridium tyrobutyricum was purchased from the American Type Culture Collection located in Washington, USA.

[0031] The enriched medium consisted of: glucose 30 g / l, yeast extract 5 g / l, peptone 5 g / l, (NH 4 ) 2 SO 4 3 g / l, K 2 HPO 4 1.5 g / l, MgSO 4 7H 2 O, 0.6 g / l, FeSO 4 7H 2 O 0.03 g / l, 50 mg / mL sodium butyrate, culture conditions: 37°С, pH 6.0, anaerobic env...

Embodiment 2

[0039] What the present embodiment provides is the technology that is the carbon source fiber bed immobilization Clostridium tyrobutyricum fed-batch fermentation butyric acid with the bagasse hydrolyzate, and the steps are as follows:

[0040] 1) same as embodiment 1 step 1);

[0041] 2) same as embodiment 1 step 2);

[0042] 3) Same as step 3 of embodiment 1);

[0043] 4) The operation steps are the same as step 4) of Example 1, except that when the sugar concentration in the fermentation broth is close to 0, bagasse hydrolyzate is added, and a total of 3 batches are added until the final concentration of the fermentation product butyric acid no longer increases. The total sugar concentration did not decrease after 186 hours of fermentation, and the final concentration of butyric acid was 62.8 g / L as measured by gas chromatography. Kinetics of butyric acid in fed-fed fermentation as image 3 shown.

Embodiment 3

[0045] What the present embodiment provides is the technology that is that carbon source fiber bed immobilized Clostridium tyrobutyricum ferments repeatedly batches of butyric acid with the bagasse hydrolyzate, and the steps are as follows:

[0046] 1) same as embodiment 1 step 1);

[0047] 2) same as embodiment 1 step 2);

[0048] 3) Same as step 3 of embodiment 1);

[0049] 4) The operation steps are the same as step 4) of Example 1, the difference is that during the fermentation process, when the sugar concentration is close to 0, the fermentation medium of bagasse hydrolyzed liquid is replaced, and a total of 5 batches are replaced. The average final concentration of butyric acid measured by gas chromatography is 22.9 g / L, the kinetics of repeated batch fermentation of butyric acid is as follows Figure 4 shown.

technical field

[0001] The invention relates to a process for producing butyric acid, in particular to a process for producing butyric acid by using Clostridium tyrobutyricum to ferment bagasse hydrolyzate, and belongs to the technical field of organic acid fermentation. Background technique

[0002] N-butyric acid (Butyric acid, hereinafter referred to as butyric acid), also known as butyric acid, has four carbon atoms in its molecule and is a short-chain saturated fatty acid connected in a straight-chain manner. It has a pungent odor, and very dilute solutions also have sweaty odor. taste. Butyric acid often exists in nature in the form of ester or free state. Butyric acid is a versatile fine chemical widely used in food, chemical and pharmaceutical industries. It is used in the preparation of candy and beverage flavoring agents in the food industry, and in the preparation of fruit flavors in the spice industry; cellulose butyrate is superior to cellulose acetate in term...

Examples

Embodiment 1

[0029] What present embodiment provides is the technology that carries out fiber bed immobilization Clostridium tyrobutyricum batch fermentation butyric acid with bagasse hydrolyzate as carbon source, and the steps are as follows:

[0030] 1) Dip the Clostridium tyrobutyricum bacteria liquid with an inoculation needle, streak on the enhanced medium plate containing 50 mg / mL sodium butyrate, and culture at 37 °C for 72 hours. The classification and naming of Clostridium tyrobutyricum (No. ATCC 25755): the Chinese name is Clostridium tyrobutyricum, and the Latin literary name is Clostridium tyrobutyricum , Clostridium tyrobutyricum was purchased from the American Type Culture Collection located in Washington, USA.

[0031] The enriched medium consisted of: glucose 30 g / l, yeast extract 5 g / l, peptone 5 g / l, (NH 4 ) 2 SO 4 3 g / l, K 2 HPO 4 1.5 g / l, MgSO 4 7H 2 O, 0.6 g / l, FeSO 4 7H 2 O 0.03 g / l, 50 mg / mL sodium butyrate, culture conditions: 37°С, pH 6.0, anaerobic env...

Embodiment 2

[0039] What the present embodiment provides is the technology that is the carbon source fiber bed immobilization Clostridium tyrobutyricum fed-batch fermentation butyric acid with the bagasse hydrolyzate, and the steps are as follows:

[0040] 1) same as embodiment 1 step 1);

[0041] 2) same as embodiment 1 step 2);

[0042] 3) Same as step 3 of embodiment 1);

[0043] 4) The operation steps are the same as step 4) of Example 1, except that when the sugar concentration in the fermentation broth is close to 0, bagasse hydrolyzate is added, and a total of 3 batches are added until the final concentration of the fermentation product butyric acid no longer increases. The total sugar concentration did not decrease after 186 hours of fermentation, and the final concentration of butyric acid was 62.8 g / L as measured by gas chromatography. Kinetics of butyric acid in fed-fed fermentation as image 3 shown.

Embodiment 3

[0045] What the present embodiment provides is the technology that is that carbon source fiber bed immobilized Clostridium tyrobutyricum ferments repeatedly batches of butyric acid with the bagasse hydrolyzate, and the steps are as follows:

[0046] 1) same as embodiment 1 step 1);

[0047] 2) same as embodiment 1 step 2);

[0048] 3) Same as step 3 of embodiment 1);

[0049] 4) The operation steps are the same as step 4) of Example 1, the difference is that during the fermentation process, when the sugar concentration is close to 0, the fermentation medium of bagasse hydrolyzed liquid is replaced, and a total of 5 batches are replaced. The average final concentration of butyric acid measured by gas chromatography is 22.9 g / L, the kinetics of repeated batch fermentation of butyric acid is as follows Figure 4 shown.

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