Nowadays, bromelain preparation products mostly appear in the market in the form of solid powder. Due to the different production processes, they have very different enzyme activities. The price of bromelain preparation will increase exponentially as the enzyme activity of its product increases. It is essential to maintain high activity for bromelain preparations in specific scenarios, such as those used in medicine. Therefore, how to optimize the production process of bromelain to reduce its cost is a crucial problem.

In this regard, we put forward some possible optimization measures. These measures will provide the factories producing enzyme preparations with ideas to improve the process flow and help enzyme preparations to be better used in life.

After investigating the basic structure of the common Bacillus subtilis fermentors and combining with the actual fermentation experience of our team, we summarized the main problems in the existing fermentation equipment as follow.

1. Most of the existing fermentation tanks have large resistance in the stirring process and are unable to drive the stirring rod up and down, which makes the raw materials mixed unevenly and makes the raw materials covered in the middle and bottom of the tank can not fully react with the oxygen in the tank.

2. The fermentation tank will generate a large number of bubbles during the fermentation, which not only occupies space and causes raw material overflow, but also affects oxygen dissolution in the fermentation tank.

3. The oxygen source of the fermentation tank is the clean air after dust removal and sterilization. Its temperature is different from the temperature of the fermentation broth, which leads to the need for the temperature control system to continuously regulate the temperature of the broth. This not only consumes a lot of energy but also is not conducive to fermentation production.

In order to solve the problems above, we continued to carry out research. After searching for a large number of the relevant invention patents, we integrated and optimized the exiting designs and finally obtained the sketches.

The main part of the fermentation tank is divided into two parts:the tank body part and the control part. The main part (tank body part) is equipped with pH, dissolved oxygen and other detection devices. Through the cooperation of the mixing blade, through-hole, coupling and cylinder, the resistance during mixing can be effectively reduced, and the mixing rod can be driven up and down, so that the upper and lower raw materials can be mixed more evenly. Besides, the bubble breaking device is built to reduce the number of bubbles in the tank.

The control part is equipped with a simple control panel to regulate the temperature and the stirring speed. The liquid in the fermentation tank enters the heating box driven by the water pump and circulates continuously. The heating box heats the clean air and liquid through two heating rods,which makes the environment in the tank more controllable and reduces energy consumption.

Our products can finally be targeted to individual users who intend to use recombinant bromelain on farms or breeding bases, so an industrial workshop process is completely unnecessary. Often, a good effect can be achieved by simply and roughly breaking the enzyme solution, and fine protease separation may only increase the cost. However, through our research, it is not entirely without merit to have a simple and efficient integrated separation device in the production base, and expensive and precise instruments will not be involved.

The prototype we seek is inspired by the process of industrial protease preparation, but instead of the large-scale production in the workshop, we focus on miniaturization and integration, but the performance will not be weakened. A peristaltic pump between the processing links can be controlled by a computer. Perhaps a small embedded chip can control the whole process because the whole process does not desire massive calculation, which will greatly improve the automation level of small-scale production. Only by simply connecting the fermentation tank of the enzyme and the separation process, high-purity enzyme preparations can be obtained.

In any case, the challenge must be objective. The first problem comes from reliability, because we are thinking of a sort of production equipment for agriculture, and its application environment may be undesirable, so its reliability should be well guaranteed; The second is maintainability. We hope our future design will be more concise. Even users who do not have a complete understanding of the mechanical principle can easily complete the maintenance and component replacement of the equipment.

Most of the feed enzyme products are microecological preparations with poor stability. Moreover, the conditions under which it plays the best role are different from the actual environmental conditions in production and life. Feeding enzyme products are very sensitive to high temperature, low temperature, ambient humidity and pH. If not properly treated, they are easy to lose their activity and have short service life. At present, the research of stabilization treatment of enzyme preparation is not deep enough, and there is no perfect stabilization method considering cost and effect. Direct addition of enzyme preparation during use will cause certain loss, while adding enzyme preparation after pelleting will cause adhesion between enzyme preparation and feed surface. Wear and tear in the process of preservation and transportation is also obvious. These losses are undoubtedly an important obstacle to the large-scale application of enzyme preparations.

In addition, powdered solid enzyme preparations are easy to dust, easy to cause losses when added and fed, and easy to inhale into the digestive tract by the human body, affecting the human body.

In order to improve the stability of bromelain in the process of production, storage and transportation, and minimize the tendency of particles to dust, we investigated the existing enzyme preservation methods by combining several literatures and patents. After fully considering the greater tolerance of enzyme purity in specific application scenarios, as well as the requirements of cost and process complexity in the processing process, we chose the following process as the processing method of our bromelain feed enzyme preparation.

The liquid concentrate containing bromelain was mixed with magnesium sulfate and dried in a spray facility to give a stabilized powder containing bromelain and, at the same time, to obtain the attached particles. The dry powder containing bromelain was then mixed with a solid organic carrier (we chose starch as the solid carrier) and sprayed with soybean oil.

The enzyme preparations produced by this technique have been described as producing solid enzyme preparations with a high degree of separation stability and an extremely low tendency to dust. In addition, it has excellent rheological properties.

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