Method for reducing thallus loss caused by foam overflow in microbial fermentation process for cigarettes

Abstract

The invention belongs to the technical field of tobacco processing, and relates to a method for reducing thallus loss caused by foam overflow in the fermentation process of tobacco microorganisms, which comprises the following steps: 1, adding culture medium mother liquor; adding the culture medium mother liquor into a three-stage fermentation tank, and supplementing water to 85-90% of the total amount of the required culture medium; 2, sterilizing the culture medium; sterilizing the culture medium through steam, wherein condensed water carried by the steam accounts for 10-15% of the total amount of the required culture medium; 3, transferring the bacteria from the second-stage tank to a third-stage fermentation tank, wherein the bacteria liquid amount of the bacteria transferred from the second-stage tank is 10% of the final liquid amount; the total liquid amount does not exceed 60% of the liquid volume of the third-stage fermentation tank; by adopting a three-stage fermentation process of quantitative liquid filling, limiting the air flow, the stirring speed, the culture temperature, the tank pressure and the culture time and increasing the volume of the residual space in the fermentation tank, the foam overflow amount is reduced, the liquid filling amount is reduced, but the number of obtained thalli is increased, the stability of the centrifugal amount of thalli in each batch is effectively improved, and the production cost is reduced. The requirements of subsequent fermentation are met.

Description

Technical Field

[0001] The present invention belongs to the technical field of tobacco processing, and relates to a method for reducing the loss of bacterial cells due to foam overflow during the fermentation of tobacco with microorganisms. Background Art

[0002] The tobacco microbial fermentation technology utilizes the fermentation and transformation function of microorganisms, aims at improving the sensory quality of tobacco leaves, screens beneficial microorganisms on the surface of tobacco leaves, conducts fermentation and cultivation, forms a compound microbial agent according to the action effect, sprays it on the surface of tobacco leaves (threads), forms a dominant flora, and ferments the tobacco leaves (threads) by controlling the fermentation conditions. The chemical components in the tobacco leaves are transformed, the substances that produce bad odors during combustion in the original tobacco leaves are removed, the proportion of chemical components in the tobacco leaves becomes more appropriate and coordinated, and natural aroma components are generated, ultimately achieving the purpose of improving the internal quality of tobacco leaves and cut tobacco.

[0003] However, foam will be generated during the production process of tobacco microbial fermentation. When the amount of foam is large, it will overflow, resulting in a decrease in the yield. In some cases, when the yield loss is too large, the fermentation batch will fail. For the foam during the fermentation and large-scale production of microbial strains, the prior art usually uses antifoaming agents to inhibit the amount of foam or defoaming agents to eliminate the foam in order to reduce the foam and increase the yield. However, due to the different selections of antifoaming agents and defoaming agents, the antifoaming and defoaming effects are also different, and it cannot fully meet the production needs.

[0004] Therefore, how to reduce the loss of bacterial cells due to the foam generated during the production process of tobacco microbial fermentation has always been a technical problem concerned by tobacco manufacturers. Summary of the Invention

[0005] The technical solution adopted by the present invention to solve the technical problem is: a method for reducing the loss of bacterial cells due to foam overflow during the fermentation of tobacco with microorganisms, comprising the following steps:

[0006] Step 1: Add the culture medium mother liquor; after adding the culture medium mother liquor into the third-stage fermentation tank, make up water to 85% - 90% of the total required culture medium amount;

[0007] Step 2: Sterilize the culture medium; sterilize the culture medium through steam, and the condensed water carried by the steam accounts for 10% - 15% of the total required culture medium amount;

[0008] Step 3: Transfer bacteria from the second-stage tank to the third-stage fermentation tank, and the amount of the bacterial liquid transferred from the second-stage tank is 10% of the total liquid filling amount;

[0009] The total liquid filling amount does not exceed 60% of the liquid filling capacity of the third-stage fermentation tank.

[0010] Preferably, the total liquid filling amount is 45% - 55% of the liquid filling capacity of the third-stage fermentation tank.

[0011] More preferably, the total liquid filling amount is 49% - 51% of the liquid filling capacity of the third-stage fermenter.

[0012] Preferably, the air flow rate during the cultivation in the third-stage fermenter is: 20 - 80 m 3 / h.

[0013] Preferably, the stirring speed during the cultivation in the third-stage fermenter is: 40 - 100 r / min.

[0014] Preferably, the temperature during the cultivation in the third-stage fermenter is: 36 - 38 °C.

[0015] More preferably, the temperature during the cultivation in the third-stage fermenter is: 36.7 - 37.3 °C.

[0016] Preferably, the tank pressure during the cultivation in the third-stage fermenter is: 0.04 - 0.06 MPa.

[0017] Preferably, the cultivation time during the cultivation in the third-stage fermenter is: 8 - 24 h.

[0018] The beneficial effects of the present invention are as follows:

[0019] By adopting a three-stage fermentation process with quantitative liquid filling, and by limiting the air flow rate, stirring speed, cultivation temperature, tank pressure, cultivation time and increasing the remaining space volume in the fermenter, the present invention reduces the amount of foam overflow, reduces the liquid filling amount but increases the number of obtained bacterial cells, effectively improves the stability of the centrifugation amount of bacterial cells in each batch, and meets the requirements of subsequent fermentation. Specific Embodiments

[0020] The following will clearly and completely describe the relevant technologies in the present invention in combination with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0021] The method for reducing the loss of bacterial cells due to foam overflow during the fermentation of tobacco microorganisms in this specific embodiment has the following liquid filling process for the third-stage fermenter:

[0022] 1. The liquid filling in the fermenter consists of three parts, namely:

[0023] 1) The mother liquor of the culture medium; after this mother liquor is added to the tank, water should be added to 85% - 90% of the total required culture medium.

[0024] 2) During the sterilization of the culture medium, a certain amount of condensed water will be brought in by the steam, which is 10% - 15% of the total required culture medium.

[0025] 3) The amount of the bacterial liquid transferred from the secondary tank is 10% of the total liquid charged.

[0026] 4) The total amount of the liquid charged shall not exceed 60% of the liquid capacity of the third-stage fermentation tank. The control requirements for the process parameter indicators of the liquid culture in the third-stage fermentation tank of the tobacco-use microbial strains are referred to Table 1.

[0027] Table 1

[0028]

[0029] 2. Liquid charging process

[0030] 1) Prepare the culture medium mother liquor according to the process requirements, add it into the tank, start stirring, and after adding an appropriate amount of water, cover the feeding port tightly.

[0031] 2) During the actual sterilization process of the culture medium, a certain amount of condensed water will be brought in by the steam, increasing the volume of the culture medium after sterilization. Therefore, after the mother liquor is added into the tank, water should be added to about 85% - 90% of the total required amount of the culture medium, and the remaining 10% - 15% is the steam condensate.

[0032] 3) After the actual sterilization is completed, compressed air should be immediately introduced to maintain the tank pressure and the tank should be cooled naturally. When the temperature drops to the culture requirement, the pressure in the tank should be maintained until inoculation.

[0033] 4) When the temperature of the culture medium drops to the inoculation temperature, inoculation can be carried out. The amount of the inoculated and transferred bacterial liquid is 10% of the required liquid charging amount in the tank of this stage.

[0034] Example

[0035] In this example, fermentation with a liquid charging amount of 1500 L, which is 50% of the volume of the fermentation tank, is taken as the example, and fermentation with a liquid charging amount of 2100 L, which is 70% of the volume of the fermentation tank, is taken as the comparative example, and the two are compared.

[0036] In the production of the bacterial fermentation for improving the sensory quality of tobacco by using microorganisms in this example, it is different from the general requirements for tobacco fermentation. The pursuit of the efficiency of tobacco fermentation and the output of tobacco fermentation is not the main goal. The most important goals pursued in the production process of this example are the stability of the number of bacteria obtained from tobacco fermentation and the stability of the activity of bacteria.

[0037] Regarding the problem that in the fermentation production process of individual strains of bacteria, the amount of foam is extremely large, often overflowing over the top, resulting in a large loss of bacteria, and in some batches, the number of bacteria often fails to reach the minimum requirement for batch production, affecting normal production. In this example, the method of reducing the liquid charging amount and increasing the remaining space in the fermentation tank is adopted to reduce the amount of foam overflow.

[0038] In this embodiment, a liquid filling volume of 50% is adopted, and fermentation is carried out under the conditions of the same culture medium formula, inoculum size, and fermentation process parameters. The test results are shown in Table 2 below:

[0039] Table 2

[0040]

[0041] It can be seen from the experimental results that when normal production fermentation is carried out with a liquid filling volume of 2100L, which is 70% of the fermentation tank volume, there is a phenomenon of foam overflow. The foam overflow volume of individual batches is relatively large. After cooling, there is a certain amount of loss in the amount of bacterial liquid, resulting in a large fluctuation in the centrifugation amount of bacteria. The range reaches 2.53 kg, and in one batch, there is only 7.55 kg, which is lower than the minimum bacterial demand of 8.5 kg for cut tobacco in a batch.

[0042] When fermentation is carried out with a liquid filling volume of 1500L, which is 50% of the fermentation tank volume, there is almost no foam overflow, and the centrifugation amount of bacteria is relatively stable. The bacterial numbers obtained in the four tests all meet the minimum quantity requirements, and the range is only 0.31 kg.

[0043] Although in this embodiment, the liquid filling volume is adjusted from 70% to 50% of the fermentation tank volume under the same fermentation conditions, the average value of the obtained bacterial quantity increases from 8.98 kg to 9.757 kg, an increase of 8.65%. Reducing the liquid filling volume actually increases the obtained bacterial quantity. Therefore, for the fermentation process of individual strains with a large amount of foam generation, a large overflow volume, and a large loss, this embodiment adopts the method of appropriately reducing the liquid filling volume and increasing the remaining space volume in the fermentation tank, which can reduce the foam overflow volume, effectively improve the stability of the centrifugation amount of bacteria in each batch, and meet the requirements of subsequent fermentation.

[0044] In summary, the present invention adopts a three-stage fermentation process with quantitative liquid filling, limits the air flow rate, stirring speed, culture temperature, tank pressure, culture time, and increases the remaining space volume in the fermentation tank, reduces the foam overflow volume, reduces the liquid filling volume but increases the obtained bacterial quantity, effectively improves the stability of the centrifugation amount of bacteria in each batch, and meets the requirements of subsequent fermentation.

[0045] It should be emphasized that the above are only the preferred embodiments of the present invention, and there is no any form of limitation to the present invention. Any simple modification, equivalent change, and modification made to the above embodiments based on the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A method for reducing the loss of bacteria due to foam overflow during tobacco microbial fermentation, characterized in that: The following steps are involved: Step 1, adding culture medium mother liquor; adding the culture medium mother liquor into the third-stage fermentation tank and then adding water to 85% to 90% of the total required culture medium amount; Step 2, sterilizing the culture medium: sterilizing the culture medium by steam, wherein the condensed water carried by the steam accounts for 10% to 15% of the total amount of the culture medium required; Step 3, transferring the bacteria from the secondary tank to the tertiary fermentation tank, wherein the amount of bacterial liquid transferred from the secondary tank is 10% of the total liquid volume; The total liquid volume does not exceed 60% of the liquid volume of the tertiary fermentation tank.

2. The method for reducing the loss of bacteria due to foam overflow in the tobacco microbial fermentation process according to claim 1, characterized in that: The total liquid filling volume is 45% to 55% of the liquid filling capacity of the tertiary fermentation tank.

3. The method for reducing the loss of bacteria due to foam overflow in the tobacco microbial fermentation process according to claim 2, characterized in that: The total liquid volume is 49% to 51% of the liquid volume of the tertiary fermentation tank.

4. The method for reducing the loss of bacteria due to foam overflow in the tobacco microbial fermentation process according to claim 1, characterized in that: The air flow rate during the three-stage fermentation tank cultivation is: 20-80m 3 / h.

5. The method for reducing the loss of bacteria due to foam overflow in the tobacco microbial fermentation process according to claim 1, characterized in that: The stirring speed during the cultivation in the three-stage fermentation tank is 40-100 r / min.

6. The method for reducing the loss of microorganisms due to foam overflow during tobacco microbial fermentation according to claim 1, characterized in that: The temperature during cultivation in the three-stage fermentation tank is 36-38°C.

7. A method for reducing the loss of bacteria due to foam overflow during tobacco microbial fermentation according to claim 6, characterized in that: The temperature during cultivation in the three-stage fermentation tank is 36.7-37.3°C.

8. The method for reducing the loss of microorganisms due to foam overflow during tobacco microbial fermentation according to claim 1, characterized in that: The tank pressure during the culturing in the three-stage fermentation tank is 0.04-0.06MPa.

9. The method for reducing the loss of microorganisms due to foam overflow during tobacco microbial fermentation according to claim 1, characterized in that: The culture time of the three-stage fermentation tank culture is 8 to 24 hours.

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