CN101003785A - Technique and equipment for producing enzyme by white rot fungus in high efficiency - Google Patents

Abstract

The extracellular enzyme system of white rot fungi has non-specific degradation performance, so that pollutants do not need to enter the cells, so that the fungus has the ability to act on insoluble, toxic, and different structures. This special degradation mechanism makes it have a strong ability to degrade various refractory organic pollutants including lignin, polycyclic aromatic hydrocarbons, chlorinated aromatic hydrocarbons, dyes, explosives, pesticides, etc., showing great application prospects. The enzyme is more widely used after separation and purification. However, the yield of the enzyme in nature is very low, and it is necessary to promote the production of a large amount of the enzyme if the enzyme is to be applied on a large scale industrially. The present invention designs an improved airlift reactor in combination with the characteristics of enzyme production by white rot fungi, which not only can effectively improve the enzyme production efficiency, but also has the characteristics of simple structure, no moving parts, and convenient operation and maintenance. In terms of operation, the reactor adopts an open system, so that the operation and maintenance cost of the reactor is greatly reduced, and it is also easier to carry out large-scale industrial production.

Description

A high-efficiency enzyme production process and device for white rot fungi

Technical field What the present invention relates to is a kind of process and device of high-efficiency enzyme production bioreactor.

Application of white rot fungal enzyme system:

1) Paper industry White-rot fungus enzyme system, on the one hand, can be used to transform the old papermaking process for biopulping, biobleaching and biodecolorization. Biopulping pretreatment reduces energy consumption and increases pulp tension. On the other hand, it can be used in the treatment of papermaking wastewater, which can significantly reduce the COD concentration, color and toxicity of wastewater.

2) Biological fertilizer can accelerate the process of high-temperature composting to convert straw into organic fertilizer, and reduce labor intensity.

3) Feed industry The feed treated with white rot fungus enzyme system can improve the digestibility of feed for animals, and the straw treated with this fungus can also be used as feed for raising pigs and chickens. Feed multi-enzyme compound additives composed of ligninase and the like can be made into commercial products for sale.

4) Fermentation and food industry The bacteria can be used for alcohol fermentation or organic acid fermentation of straw. In the food industry, beer, fruit juice, etc. often appear turbid or precipitated during storage, and its enzyme can be used to remove precipitation and flocculation, so that wine can be clarified.

5) Environmental protection It has the ability to degrade a variety of organic compounds, and is widely used in chemical organic wastewater treatment such as pesticide degradation, dye decolorization, and military wastewater degradation. The white rot fungal enzyme system can also be used for bioremediation of pollutant accumulation sites and soil contaminated by pesticide erosion, petroleum hydrocarbons, polychlorinated biphenyls, TNT, DDT, etc.

6) Others The basic structure of coal and petroleum is similar to lignin, so the white rot fungal enzyme system can be used to depolymerize and solubilize coal, avoiding the air pollution caused by direct use of coal; the bacteria can also be used to treat coal and petroleum for desulfurization. The deep processing of coal and petroleum into efficient clean energy.

Background technology At present, domestic and foreign researches on how to improve the yield of white rot fungal enzyme system and the development of related reactors have been carried out, and some effective technologies have also been formed. Some technologies developed and used at home and abroad in recent years are summarized as follows.

① Mechanically stirred reactor: Mechanically stirred reactor is the most commonly used reactor, which can be applied to most biological cultivation processes. Other types of reactors are considered only when their gas-liquid transfer properties or shear forces cannot meet the requirements of biological processes. In order to prevent the vortex of the liquid during stirring, a baffle can be installed inside the reactor to enhance the radial mixing of the liquid. Because the enzyme system of white rot fungi is sensitive to shear force, it is not suitable for its production.

②Fixed bed: The basic principle of the fixed bed reactor is that the reaction solution flows continuously through the stationary immobilized bacteria (or biocatalyst). The main advantage of the fixed bed is that the bacterial cells can be reused, and it is convenient to separate the bacterial cells from the reaction products, but the white-rot fungal enzyme system requires a certain oxygen partial pressure, so its effect is not good.

③ Trickle bed: Packed bed is suitable for the continuous enzyme production process of immobilized microbial cells. Generally, the reaction solution containing higher concentration products flows out from the upper end. In this case, the amount of immobilized particles per unit volume of the reactor is much larger than that of the fluidized bed. However, due to the long-term static accumulation of immobilized cells, with the continuous growth of cells, it is easy to cause poor nutrient supply. For aerobic fermentation, limited aeration to the packed bed is also possible. However, due to the dense packing of immobilized cells and the necessity to avoid fluidization, the aeration capacity is strictly limited. The yield of white rot fungal enzyme system is not high either.

④ Drum reactor: Drum bioreactors usually achieve the purpose of mixing through the rotation of the turntable or drum. The degree of mixing is general and depends on the requirements of fermentation. Usually lower spin speeds are used, and high spin mixing is rarely used. The reason is that the high rotation speed will damage the mycelium, and can generate too much heat, which will affect the microbial production of enzymes and other secondary metabolites. The diameter of the drum of the drum reactor should not be too long and the volume should not be too large, otherwise it will not only be difficult to operate, but also cause the medium to form a ball during the rotation process, thereby affecting the utilization of nutrients by microorganisms.

⑤ Bubble tower: The main body of the bubble tower is a container, usually cylindrical, with a ratio of height to diameter of 4-6. The reaction solution is ventilated at the bottom of the vessel through perforated tubes, perforated discs, sintered glass, sintered metal or microporous sprayers. To enhance mixing, a series of horizontal perforated plates, vertical baffles, etc. can also be installed inside the vessel. The advantages of the bubble tower are that no mechanical transmission equipment is required, the power consumption is small, and it is not easy to pollute the bacteria; the disadvantage is that it cannot provide high enough shear force, the mass transfer efficiency is low, and filamentous bacteria such as white rot fungi sometimes form large The mycelial mass affects metabolism and product synthesis.

⑥ Airlift reactor: Airlift reactor is the most widely used bioreactor, which is developed on the basis of bubble column. It uses the jet function of the air and the difference in fluid density to cause the reaction liquid to circulate, so as to realize the stirring, mixing and oxygen transfer of the liquid. That is to say, without mechanical stirring (avoiding the entanglement and attachment of mycelium), the liquid is completely dependent on the lifting of the gas to make the liquid circulate and turbulent, so as to achieve the purpose of gas-liquid mixing and transmission. Its container is divided into two connected areas by a partition or a draft tube, of which only one area is ventilated. The ventilated area is called the ascending zone, and the unventilated area is called the descending zone. As the bubbles in the uplink area flow upward, the liquid is driven to move from bottom to top, and after being separated from the gas at the top, it goes down along the downlink area, and so on. Sometimes the uplink zone and the downlink zone can be a container respectively, and the two are connected by pipes at the bottom and top. Such an airlift reactor is called an external circulation airlift reactor. Compared with the stirred tank, the airlift reactor adds a device to promote fluid circulation, which greatly improves the interphase mixing and contact conditions, which is beneficial to the mass transfer and reaction process, and has a simple structure (no moving parts inside), no need for stirring , saving energy, high oxygen mass transfer efficiency, not easy to pollute, small shear force, convenient installation and maintenance, etc., especially suitable for microbial cells that are sensitive to shear force. However, the reactor is generally operated in a sterile environment, and the cost is relatively high.

Problems with existing reactors:

●It cannot meet the oxygen partial pressure required by the white rot fungal enzyme system and avoid the damage of the enzyme activity by the shear force;

●Maintenance and operation costs are relatively high;

Therefore, aiming at the problems existing in the existing reactors, the present invention aims to develop an economical and practical white-rot fungus high-efficiency enzyme production process and device, so as to promote the practical application of white-rot fungal enzyme systems in various aspects in our country.

Table 1: Performance comparison of different reactors

Summary of the invention In the research, it was found that the structure of the reactor itself, such as the diameter-to-height ratio, and the ratio of internal and external diameters, are also very important factors affecting the enzyme production efficiency of white rot fungi. The inventors based on the traditional airlift reactor, according to The characteristics of the enzyme system of white rot fungi, after a large number of experiments, the traditional airlift reaction has been improved, so that the fungus can attach and grow in the part of the airlift reactor where the shear force is small. At the same time, considering the cost of industrial production, aiming at the shortcomings of high operation and maintenance costs of the aseptic culture method, an open culture method is adopted, which greatly reduces the production and maintenance costs. The optimized reactor has stable enzyme production effect and convenient maintenance. , Easy to automate features.

In order to improve the productivity of the white-rot fungal enzyme system, the present invention has carried out comprehensive experimental research on parameters such as temperature, nutritional parameters, operation mode, medium replacement ratio, aeration rate and the like. The results of the study showed that the enzyme production efficiency was greatly improved through the optimal combination of the above factors. Therefore, through the treatment of the above optimized combination, the yield is effectively improved, which is the content of the first item of the claims of the present invention.

Main technical scheme of the present invention is as follows:

After immersing and sterilizing the reactor with an appropriate disinfectant for 12-24 hours, rinse the disinfectant in the reactor with sterile water, add an appropriate amount of sterilized medium into the reactor, and inoculate an appropriate amount Finally, maintain a suitable temperature for culturing to produce enzymes. After the enzyme activity reaches the highest level, replace the medium in a certain proportion to maintain the highest level of enzyme activity. At this time, the replaced enzyme can be directly used or further processed such as separation and purification.

Description of drawings:

Fig. 1 is a schematic diagram of a patent reactor of the present invention, which is an improved airlift reactor, and the main components are described as follows:

1 Air inlet; 2 Air outlet; 3 Insulation water inlet; 4 Insulation water outlet; 5 Packing; 6 Aeration head; 7 Fixing screw; 8 Sampling port;

Enzyme production and wastewater treatment effect:

The reactor was used for enzyme production, and the obtained results were compared with the literature values, as shown in Table 2. And use the produced enzyme to degrade the dye distribution water and actual waste water, which can make it reach the national sewage comprehensive discharge standard. The results show that the reactor has high enzyme production efficiency and stable operation, and its degradation effect is obviously better than other reactors no matter for dye water distribution or actual dye wastewater.

Table 2: Comparison of enzyme production efficiency and wastewater treatment effect of different reactors

Claims (3)

1 one cover white-rot fungis or similar mushroom efficiently produce enzymatic process and device, it is characterized in that in special purpose reactor, by controlling the productive rate that working conditions such as substratum concentration and displacement ratio, temperature of reaction, operating method, aeration rate improve white-rot fungi extracellular enzyme system.

2 according to claim 1, and this technology and device are applicable to and improve white-rot fungi and the fungi enzyme productive rate of class thereof that optimal processing parameter comprises factors such as substratum, temperature of reaction, operating method, aeration rate.

3 this patents are reactor used to be a kind of improved airlift reactor, and its principal feature is to satisfy the demand of fungi to oxygen supply and appropriate shearing force simultaneously.

Images