Optimization of the Cultivation Device for Cordyceps militaris and Development of Its Characteristic Product

Xiong YAN Wenzhao LI Peng ZHANG Jie HE Xiaoqin LUO Zhou LI

Abstract  In order to better promote the development of the  Cordyceps militaris  industry， the  C. militaris  cultivation device was optimized. Multiple layers of bearing plates are arranged on a support frame， and six cultivation boxes are placed on each layer of bearing plate. The optimized device improves the cultivation method of  C. militaris ， improves the space utilization rate， and can greatly increase the output of  C. militaris . Meanwhile， combining with local special  R. roxburghii  in Guizhou， a  C. militaris  and  R. roxburghii  compound drink were developed， which extends the industrial chain of  C. militaris ， which meets the current social needs and has good market prospects. The research results can promote rural industrial revolution and further help the revitalization of rural industries.

Key words   Cordyceps militaris ; Cultivation device; Special product

Natural  Cordyceps militaris  infects live larvae with  Cordyceps  mycelia and absorbs nutrients from the larvae， and the larvae are filled with  Cordyceps  mycelia and die， becoming stiff pupae.  Under  suitable conditions， the mycelia of  Cordyceps  fungus grows and reproduces in the stiff pupae to form stromata， which continue to grow from the head or other parts into rod-shaped fruiting bodies， which look like grass， and the complexes are called  " C. militaris ".   C. militaris  belongs to the fungus kingdom  （fungi）   [1] ， and is a model fungus of the genus  Cordyceps   [2] . It is a treasure of nature. Because it is rich in biologically active substances such as cordycepin， cordycepic acid， cordyceps polysaccharides， SOD，  etc. ， its medicinal value is very significant.

Due to the scarcity of natural resources of  C. militaris ， artificial cultivation methods are now used to obtain  C. militaris . Artificial cultivation requires light of different wavelengths， and different light intensities and light time according to the different growth stages of mycelia and fruit bodies. However， the existing cultivation method of directly placing  C. militaris  cultivation boxes on the ground cannot realize large-scale industrial production， and has a long growth cycle， low space utilization rate and high cost.  In this study， a  C. militaris  cultivation device was designed to solve the problem of low space utilization rate when cultivating   C. militaris   in the prior art. On the other hand， based on the  medicinal  value and use value of  C. militaris ， many derivative products containing  C. militaris  have appeared on the market， such as  C. militaris  noodles  [3] ， enzyme drinks  [4] ， and yogurt  [5] ，  etc.  In this study， combining with the local special  Rosa roxburghii  in Guizhou， a   C. militaris   and  R. roxburghii  compound drink was developed. This special product has the characteristics of comprehensive nutritional value and good taste， and can further extend the enrichment chain of the  C. militaris  industry.

Materials and Methods 

C. militaris  cultivation devices

Improvements are made on the basis of existing cultivation devices on the market， and the required materials include support frames， support plates， LED lights， cultivation boxes， motors，  etc.

C. militaris  and  R. roxburghii  compound drink

The drink included selected  R. roxburghii  fruit puree，   C. militaris   fruiting body slurry， and other auxiliary materials to adjust the taste of the beverage.

Results and Analysis 

Optimization of  C. militaris  cultivation device 

Design of cultivation device

The schematic diagram of the structure of the  C. militaris  cultivation device is shown in Fig. 1. It includes a support frame， on which a plurality of horizontal support plates are fixed in parallel at intervals and connected in a rotatable manner to the same rotating tube， which is perpendicular to the support plates and runs through the geometric center of the support plates. Two LED lights are arranged on the lower surface of each support plate， and the two LED lights are symmetrically arranged based on the rotating tube. There is a bearing plate directly under each support plate， and a through hole is set on each bearing plate. Each through hole is located in the center of corresponding bearing plate and is fixedly connected with the rotating tube. Each bearing plate is detachably connected with six cultivation boxes （Fig. 2）， which are all evenly distributed around the rotating tube， and six LED lights are arranged right above the cultivation boxes in one-to-one correspondence. The rotating tube is provided with a number of air outlet holes， which are located between the bearing plate and the support plate. In the rotating tube is provided a humidifying pipe， on which a number of steam exhaust holes are provided. One end of the humidifying pipe is connected with a humidifier， which is located on the support frame. The support frame is also provided with a stepping motor that drives the rotating tube to rotate.

Advantages of the cultivation device

Since the six cultivation boxes are evenly distributed around the rotating tube， one of the cultivation boxes is located directly under one LED light， and another cultivation box that is symmetrical with this cultivation box is located directly under another LED， so when the stepping motor drives the rotating tube to rotate， the bearing plates and the cultivation boxes also rotate with the rotating tube， and the cultivation boxes evenly distributed on the bearing plates will pass directly under the LED lights on the support plates directly above the  bearing  plates. In use， inoculated cultivation boxes are placed on the bearing plates， and the mycelia are initially cultivated in the dark， with the room temperature controlled at 21-23 ℃ and the air humidity maintained at 60%. After the mycelia cover the surface， the culture is continued for 7-10 d. When the mycelia complete the vegetative growth， the LED lights are turned on to illuminate the cultivation boxes， and the stepping motor is started at the same time. The angular displacement of the stepping motor is controlled by the number of pulses to 60°. In this way， the stepping motor is controlled to rotate 60° in each step， then stay for  8 h ， and then continue to rotate in the next step. The above operation is repeated， so that the frequency that each cultivation box receives light is 8 h/d， under which the growth rate of  C. militaris  is fast and the growth quality is good. Meanwhile， according to the growth needs of the mycelia， the water vapor generated by the humidifier is discharged from the steam exhaust holes on the humidifying pipe， and then enters the cavity where the cultivation boxes are located through the air outlet holes on the rotating tube to adjust the humidity of the environment where the mycelia are located. The device improves the space utilization rate and increases the growth rate of the mycelia.

Research and development of  C. militaris  and  R. roxburghii  compound drink 

Preparation of C. militaris  and  R. roxburghii  compound drink 

The raw materials of this drink are  R. roxburghii  fruit puree  30-50  parts，  C. militaris  fruiting body slurry 10-15 parts and other auxiliary materials 10-20 parts. The above three types of raw materials are mixed and stirred according to the proportions， and the  C. militaris  and  R. roxburghii  beverage is obtained after sterilization. The  C. militaris  fruiting body slurry is prepared by the steps of washing and soaking  C. militaris  fruiting bodies in warm water at 60-70 ℃， and then beating to slurry and sieving.  Other auxiliary materials include sweeteners， thickeners and 3-5 parts of sea buckthorn puree， which can neutralize the bitterness of tannins in  R. roxburghii  fruit， reconcile the fishy smell of   C. militaris  ， and enrich the taste and nutritional value of the  beverage.

Advantages of the special drink

R. roxburghii  fruit is rich in vitamin C，  R. roxburghii  flavonoids，  R. roxburghii  polysaccharides， and a variety of essential amino acids and SOD and other nutrients. Because of its rich vitamins， it is also called "the king of vitamin C".  R. roxburghii  has extremely high medicinal value. It has good health care effects of enhancing the immune function of the human body， delaying aging， regulating cardiovascular function， preventing and treating stomach diseases， reducing the load of heavy metals in the body， and resisting tumors.  R. roxburghii  is a famous and high-quality special product in Guizhou， which enhances the nutritional value of compound drinks as a raw material. On the other hand， the  C. militaris  fruiting body slurry is prepared by washing the fruiting bodies of  C. militaris  and soaking them in warm water at 60-70 ℃ before beating， so that the decomposition of substances that are easily decomposed at high temperature such as polysaccharides in the boiling environment is   avoided.  Meanwhile， compared with direct beating， warm water  at 60-70 ℃  is more likely to break the walls and separate out  effective  components in the fruiting bodies of  C. militaris ， thereby reducing the retention in solid filter residues.

Conclusions and Discussion

Through the optimization of the  C. militaris  cultivation device， multiple layers of bearing plates are arranged on the support frame， and six cultivation boxes are placed on each layer of bearing plate. Compared with the cultivation method of directly supporting  C. militaris  cultivation boxes on the ground， the method in this study improved the space utilization rate， and can increase the yield of  C. militaris . Meanwhile， combining with local special   R. roxburghii   in Guizhou， the  C. militaris  and  R. roxburghii  compound drink were developed， which extends the industrial chain of  C. militaris ， which meets the current social needs and has good market prospects. The research results can promote rural industrial revolution and further help the revitalization of rural industries.

References

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 Editor： Yingzhi GUANG   Proofreader： Xinxiu ZHU