Method for improving lunar soil by phosphate-solubilizing bacteria

Abstract

The invention provides a method for improving lunar soil by phosphate-solubilizing bacteria, which comprises the following steps: respectively mixing glucose bouillon culture medium dry powder, water and three phosphate-solubilizing bacteria seed solutions in a sterile environment, and respectively carrying out shake-flask culture to activate the three phosphate-solubilizing bacteria to obtain three phosphate-solubilizing bacteria culture solutions; the three phosphate-solubilizing bacteria culture solutions are mixed according to a certain proportion and then mixed with water and glucose broth culture medium dry powder according to a certain proportion, and the lunar soil improvement microbial agent is obtained; the method comprises the following steps: mixing the lunar soil improving microbial agent with lunar soil to obtain a wet material with the mass moisture content of 10-60%; loading the wet material into a fermentation container to obtain a fermented material, and performing aerobic fermentation on the fermented material to obtain the improved lunar soil capable of being used as the plant culture medium. According to the method, the most abundant lunar soil resource on the surface of the moon is utilized and is converted into a good growth substrate for plants, so that the agricultural cost of the moon is reduced, and long-term survival of human in the moon is realized.

Description

Technical Field

[0001] The invention relates to the field of lunar agricultural technology, and in particular to a method for improving lunar soil with phosphate-solubilizing bacteria. Background Art

[0002] The moon, due to its huge resources and unique spatial location, has great value in commercial development, space exploration and even national defense security. At present, my country has planned to build a lunar base with long-term manning by 2050. However, due to the extremely long distance between the earth and the moon, it is difficult and costly to carry out the lunar base supply mission. It is estimated that the cost of food, water and oxygen supply for a lunar astronaut will reach hundreds of millions of RMB per year, which has become a major pain point in the current lunar development.

[0003] Lunar agriculture can provide food and oxygen for lunar astronauts, purify water, absorb carbon dioxide exhaled by breathing, and reduce the supply costs of long-term lunar missions. However, according to existing research, most of the mineral elements in the lunar soil currently exist in a sparingly soluble state. In particular, phosphorus basically exists in the form of sparingly soluble phosphorus, which cannot be absorbed and utilized by plants, seriously inhibiting the growth of plants in the lunar soil. Therefore, it is particularly important to find a way to improve the lunar soil and increase its fertility. Summary of the invention

[0004] In view of this, the problem to be solved by the present invention is to provide a method for improving lunar soil with phosphate-solubilizing bacteria, aiming to provide conditions that allow astronauts to use lunar soil to carry out lunar agriculture, thereby reducing the supply costs of lunar missions.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is: a method for improving lunar soil with phosphate-solubilizing bacteria, comprising the following steps:

[0006] S1: Mixing glucose broth medium powder, water and three phosphate-solubilizing bacteria seed solutions in a sterile environment, respectively, and culturing in shake flasks to activate the three phosphate-solubilizing bacteria to obtain three phosphate-solubilizing bacteria culture solutions;

[0007] S2: The culture solutions of the three phosphate-solubilizing bacteria in step S1 are mixed in a certain proportion, and then mixed with water and glucose broth medium powder in a certain proportion to obtain a lunar soil improvement microbial agent;

[0008] S3: mixing the lunar soil-improving microbial agent of step S2 with the lunar soil to obtain a wet material with a mass moisture content of 10%-60%;

[0009] S4: The wet material of step S3 is loaded into a fermentation container to obtain a fermentation material, and the fermentation material is aerobically fermented to obtain improved lunar soil that can be used as a plant cultivation medium.

[0010] In the present invention, preferably, the glucose broth medium dry powder and phosphate-solubilizing bacteria seed solution are materials carried in advance for the lunar mission; the lunar soil includes real lunar soil and simulated lunar soil, the real lunar soil is the lunar surface weathering material collected on the lunar surface, and the simulated lunar soil is a lunar soil analogue developed from Earth volcanic rocks with physical and chemical properties similar to those of the real lunar soil; the water is a material carried in advance or collected from the lunar surface.

[0011] In the present invention, preferably, the components of the glucose broth medium dry powder include peptone, yeast extract, glucose and sodium chloride in a ratio of 1:1:1:1 to 2:1:1:1.

[0012] In the present invention, preferably, the phosphate-solubilizing bacterial culture solution of step S2 includes Bacillus subtilis, Bacillus megaterium and Pseudomonas fluorescens, and the absorbance at 600 nm of the phosphate-solubilizing bacterial culture solutions when mixed is between 0.1-1.0, and the mixing volume ratio is between 1:1:0.1 and 1:10:1.

[0013] In the present invention, preferably, the mixing mass ratio of the phosphate-solubilizing bacteria culture mixture, water, and glucose broth medium dry powder in steps S1 and S2 is between 1:250:1 and 1:25:1.

[0014] In the present invention, preferably, the duration of the aerobic fermentation is 1-20 days, and the temperature of the aerobic fermentation is 15-30 degrees Celsius; during the aerobic fermentation, the fermented material is thoroughly stirred every 0.5-2 days.

[0015] In the present invention, preferably, the shake flask culture conditions in step S1 are 20-30 degrees Celsius, shaking 150-200 rpm, and culturing for 10-24 hours.

[0016] The advantages and positive effects of the present invention are as follows: compared with other methods for improving lunar soil by physical and chemical means, the method for improving lunar soil by using phosphate-dissolving bacteria disclosed in the present invention does not require the additional carrying of heavy and expensive improvers, and has the advantages of good and lasting improvement effects, further reducing the initial and long-term costs of lunar agriculture, maintaining the good productivity of the lunar agricultural ecosystem, and improving the self-sustaining capacity of the lunar base. In addition, the most abundant lunar soil resources on the lunar surface can be fully utilized to improve the fertility of the lunar soil and transform it into a matrix for the cultivation of lunar agricultural crops, thereby eliminating the need for complex hydroponic equipment and significantly reducing the initial costs of lunar agriculture. DETAILED DESCRIPTION

[0017] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0018] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0019] The present application will be described in detail below through examples. Earth's farmlands have long used phosphate-solubilizing bacteria to improve the effectiveness of phosphate fertilizers. Introducing phosphate-solubilizing bacteria into lunar soil and improving the effectiveness of lunar soil phosphorus and fertility through the activity of phosphate-solubilizing bacteria is a good way to improve lunar soil. Based on this concept and in combination with a large number of experiments conducted in the early stages, this patent proposes a method for improving lunar soil with phosphate-solubilizing bacteria, which can allow astronauts to use lunar soil to carry out lunar agriculture, thereby reducing the supply costs of lunar missions.

[0020] Control group 1: Add 20 ml of water to 100 g of simulated lunar soil, mix thoroughly and sterilize, then ferment aerobically at 30 degrees Celsius for 18 days, stir the wet material once a day, take it out after fermentation, and cultivate Nicotiana benthamiana, and culture it under light conditions for 24 days after germination.

[0021] Embodiment 1:

[0022] The present invention provides a method for improving lunar soil with phosphate-solubilizing bacteria, comprising the following steps:

[0023] S1: 1g of glucose broth medium powder and 30g of water were mixed with 1g of Bacillus subtilis seed solution, 1g of Bacillus megaterium seed solution and 1g of Pseudomonas fluorescens seed solution in a sterile environment, and shaken flasks were cultured to activate the three phosphate-solubilizing bacteria. The shaking flask culture conditions were 25 degrees Celsius, 150rpm, and cultured for 10 hours to obtain the three phosphate-solubilizing bacterial culture solutions; the components of the glucose broth medium powder include peptone, yeast extract, glucose and sodium chloride, and the ratio is between 1:1:1:1 and 2:1:1:1. Compared with the commonly used LB medium, glucose broth medium can better support the recovery growth of phosphate-solubilizing bacteria.

[0024] The three strains of phosphate-solubilizing bacteria used in this plan were selected on the basis of a large number of screening tests. According to the screening results using the Apollo 14 low-titanium lunar sea soil simulant, the three strains of phosphate-solubilizing bacteria, Bacillus megaterium, and Pseudomonas fluorescens, can not only tolerate the adverse environment of the simulated lunar soil and grow and reproduce, but can also efficiently release the insoluble phosphorus elements in the simulated lunar soil by adsorbing and acidifying the lunar soil particles, thereby improving the growth of Nicotiana benthamiana in the simulated lunar soil.

[0025] For lunar missions, glycerol bacteria can be stored in liquid nitrogen to carry phosphate-solubilizing bacteria strains to the moon, which is more cost-effective and volume-efficient. However, the activity of frozen glycerol bacteria is very poor, and shake flask culture should be carried out before being used in lunar soil improvement to revive and expand phosphate-solubilizing bacteria. Therefore, shake flask culture should be carried out on a shaker with temperature and speed control conditions.

[0026] S2: Mix and shake the three phosphate-solubilizing bacteria culture solutions in a ratio of 1:1:1, take out 0.5 ml, and mix it with 20 ml of water and 0.5 g of glucose broth medium powder to obtain a lunar soil improvement microbial agent; the absorbance at 600 nm of the phosphate-solubilizing bacteria culture solution is between 0.1 and 1.0 when mixed, and the revived phosphate-solubilizing bacteria are mixed in a certain proportion to prepare a phosphate-solubilizing bacteria culture solution mixture. Considering the complementarity of different phosphate-solubilizing bacteria in phosphate-solubilizing peak and phosphate-solubilizing mechanism, the improvement effect of using multiple phosphate-solubilizing bacteria on lunar soil is greater than that of a single phosphate-solubilizing bacteria.

[0027] In the present embodiment, further, the glucose broth medium powder and phosphate-solubilizing bacteria seed liquid are materials carried in advance for the lunar mission; the lunar soil includes real lunar soil and simulated lunar soil, the real lunar soil is the lunar surface weathering material collected on the lunar surface, and the simulated lunar soil is a lunar soil analogue developed from Earth's volcanic rocks with physical and chemical properties similar to those of the real lunar soil; the water is a material carried in advance or collected from the lunar surface.

[0028] Subsequently, the phosphate-solubilizing bacteria culture solution mixture is mixed with glucose broth medium powder and water. Glucose broth medium provides the necessary nutrients for the growth, reproduction and phosphate-solubilizing activity of phosphate-solubilizing bacteria in the lunar soil. Water is added to maintain the fermentation humidity of the wet material during the subsequent aerobic co-fermentation process, and is also conducive to the full contact between the phosphate-solubilizing bacteria and the lunar soil.

[0029] S3: Fully mix the lunar soil-improving microbial agent with 100 g of lunar soil to obtain a wet material;

[0030] S4: The wet material is placed in a fermentation container to obtain a fermentation material, and the fermentation material is aerobic fermented at 30 degrees Celsius for a total of 18 days. The wet material is stirred once a day. The purpose of stirring the wet material is to make the wet material form a loose and breathable structure, promote the aerobic respiration of phosphate-solubilizing bacteria, and enhance its activation of the phosphorus element in the lunar soil. After the fermentation is completed, the material is taken out and cultivated with Nicotiana benthamiana, and cultured for 24 days under light conditions after germination.

[0031] Comparative Example 1:

[0032] S1: 1 g of glucose broth medium powder and 30 g of water were mixed with 1 g of Bacillus mucilaginosus seed solution, 1 g of Bacillus megaterium seed solution and 1 g of Pseudomonas fluorescens seed solution in a sterile environment, and shaken flasks were cultured to activate the three phosphate-solubilizing bacteria. The shaking flask culture conditions were 25 degrees Celsius, shaking at 150 rpm, and cultured for 10 hours to obtain three phosphate-solubilizing bacterial culture solutions, and three phosphate-solubilizing bacterial culture solutions were obtained;

[0033] S2: Mix the culture solutions of the three strains of phosphate-solubilizing bacteria in a ratio of 1:1:1 and shake them evenly. Take out 0.5 ml of the solution and mix it evenly with 20 ml of water and 0.5 g of glucose broth medium powder to obtain a lunar soil improvement microbial agent.

[0034] S3: Fully mix the lunar soil improved microbial agent with 100 g of lunar soil to obtain a wet material;

[0035] S4: The wet material was directly used for cultivation of Nicotiana benthamiana and cultured under light conditions for 24 days after germination.

[0036] Comparative Example 2:

[0037] S1: 1 g of glucose broth medium powder and 30 g of water were mixed with 1 g of Bacillus mucilaginosus seed solution, 1 g of Bacillus megaterium seed solution and 1 g of Pseudomonas fluorescens seed solution in a sterile environment, and shaken flasks were cultured to activate the three phosphate-solubilizing bacteria. The shaking flask culture conditions were 25 degrees Celsius, shaking at 150 rpm, and cultured for 10 hours to obtain three phosphate-solubilizing bacterial culture solutions, and three phosphate-solubilizing bacterial culture solutions were obtained;

[0038] S2: Mix the culture solutions of the three strains of phosphate-solubilizing bacteria in a ratio of 1:1:1 and shake them evenly. Take out 0.5 ml of the solution and mix it evenly with 20 ml of water and 0.5 g of glucose broth medium powder to obtain a lunar soil improvement microbial agent.

[0039] S3: Fully mix the lunar soil-improving microbial agent with 100 g of lunar soil to obtain a wet material;

[0040] S4: The wet material is placed in a fermentation container to obtain a fermentation material, and the fermentation material is subjected to aerobic fermentation at 30 degrees Celsius for 6 days, and the wet material is stirred once a day. After the fermentation is completed, the wet material is taken out and cultivated under the light condition for 24 days after germination.

[0041] Comparative Example 3:

[0042] S1: 1 g of glucose broth medium powder and 30 g of water were mixed with 1 g of Bacillus mucilaginosus seed solution, 1 g of Bacillus megaterium seed solution and 1 g of Pseudomonas fluorescens seed solution in a sterile environment, and shaken flasks were cultured to activate the three phosphate-solubilizing bacteria. The shaking flask culture conditions were 25 degrees Celsius, shaking at 150 rpm, and cultured for 10 hours to obtain three phosphate-solubilizing bacterial culture solutions, and three phosphate-solubilizing bacterial culture solutions were obtained;

[0043] S2: Mix the culture solutions of the three strains of phosphate-solubilizing bacteria in a ratio of 1:1:1 and shake them evenly. Take out 0.5 ml of the solution and mix it evenly with 20 ml of water and 0.5 g of glucose broth medium powder to obtain a lunar soil improvement microbial agent.

[0044] S3: Fully mix the lunar soil-improving microbial agent with 100 g of lunar soil to obtain a wet material;

[0045] S4: The wet material is placed in a fermentation container to obtain a fermentation material, and the fermentation material is aerobic fermented at 30 degrees Celsius for 12 days, and the wet material is stirred once a day. After the fermentation is completed, the wet material is taken out and cultivated under the light condition for 24 days after germination.

[0046] According to the methods of Control Group 1, Example 1, and Comparative Examples 1 to 3, the plant diameter of Nicotiana benthamiana 24 days after sowing, the seedling length 6 days after sowing, the plant fresh weight 24 days after sowing, and the plant chlorophyll content 24 days after sowing were calculated. The data are as follows:

[0047] Table 1 Comparison of data between control group, embodiment and different comparative examples

[0048]

[0049] From the data of Control Group 1, Example 1, Comparative Examples 1 to 3 and Table 1, it can be concluded that the method for improving lunar soil of the present invention includes activation of phosphate-solubilizing bacteria, adding glucose broth culture medium to simulated lunar soil, inoculating phosphate-solubilizing bacteria, and aerobic co-fermentation. This patent can utilize the most abundant lunar soil resources on the lunar surface and transform them into a good growth matrix for plants, thereby reducing the cost of lunar agriculture and realizing the long-term survival of humans on the moon.

[0050] Combining the control group 1, Example 1 and Comparative Example 1, it can be seen that compared with not fermenting the wet material and directly cultivating Nicotiana benthamiana, the plant diameter and seedling length are longer, the plant fresh weight is heavier, the plant chlorophyll content is higher, the growth of Nicotiana benthamiana is faster and better, and the improved lunar soil conditions as a plant cultivation medium are better.

[0051] Combining the control group 1, Example 1 and Comparative Example 2, it can be seen that the plant diameter and seedling length are longer, the plant fresh weight is heavier, the plant chlorophyll content is higher, the growth of Nicotiana benthamiana is faster and better, and the improved lunar soil conditions as a plant cultivation medium are better when the wet material is fermented for 18 days compared to the wet material fermented for 6 days.

[0052] Combining the control group 1, Example 1 and Comparative Example 3, it can be seen that the plant diameter and seedling length are longer, the plant fresh weight is heavier, the plant chlorophyll content is higher, the growth of Nicotiana benthamiana is faster and better, and the improved lunar soil conditions as a plant cultivation medium are better when the wet material is fermented for 18 days compared to the wet material.

[0053] The embodiments of the present invention are described in detail above, but the contents described are only preferred embodiments of the present invention and cannot be considered to limit the scope of implementation of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of this patent.

Claims

1. A method for improving lunar soil with phosphate-solubilizing bacteria, characterized in that: The following steps are involved: S1: Mixing glucose broth medium powder, water and three phosphate-solubilizing bacteria seed solutions in a sterile environment, respectively, and culturing in shake flasks to activate the three phosphate-solubilizing bacteria to obtain three phosphate-solubilizing bacteria culture solutions; S2: The culture solutions of the three phosphate-solubilizing bacteria in step S1 are mixed in a certain proportion, and then mixed with water and glucose broth medium powder in a certain proportion to obtain a lunar soil improvement microbial agent; S3: mixing the lunar soil-improving microbial agent of step S2 with the lunar soil to obtain a wet material with a mass moisture content of 10%-60%; S4: The wet material of step S3 is loaded into a fermentation container to obtain a fermentation material, and the fermentation material is aerobically fermented to obtain improved lunar soil that can be used as a plant cultivation medium.

2. The method for improving lunar soil with phosphate-solubilizing bacteria according to claim 1, characterized in that: The glucose broth culture medium powder and phosphate-solubilizing bacteria seed liquid are materials carried in advance for the lunar mission; the lunar soil includes real lunar soil and simulated lunar soil. The real lunar soil is the lunar surface weathering material collected on the lunar surface, and the simulated lunar soil is a lunar soil analogue developed from Earth's volcanic rocks with physical and chemical properties similar to those of the real lunar soil; the water is a material carried in advance or collected from the lunar surface.

3. The method for improving lunar soil with phosphate-solubilizing bacteria according to claim 1, characterized in that: The glucose broth medium dry powder comprises peptone, yeast extract, glucose and sodium chloride in a ratio of 1:1:1:1 to 2:1:1:

1.

4. The method for improving lunar soil with phosphate-solubilizing bacteria according to claim 1, characterized in that: The phosphate-solubilizing bacterial culture solution in step S2 includes Bacillus subtilis, Bacillus megaterium and Pseudomonas fluorescens. The absorbance at 600 nm of the phosphate-solubilizing bacterial culture solution when mixed is between 0.1 and 1.0, and the mixing volume ratio is between 1:1:0.1 and 1: Between 10:

1.

5. The method for improving lunar soil with phosphate-solubilizing bacteria according to claim 1, characterized in that: The mixing mass ratio of the phosphate-solubilizing bacteria culture solution mixture, water, and glucose broth medium dry powder in steps S1 and S2 is between 1:250:1 and 1:25:

1.

6. The method for improving lunar soil with phosphate-solubilizing bacteria according to claim 1, characterized in that: The duration of the aerobic fermentation is 1-20 days, and the temperature of the aerobic fermentation is 15-30 degrees Celsius; during the aerobic fermentation, the fermented materials are thoroughly stirred every 0.5-2 days.

7. The method for improving lunar soil with phosphate-solubilizing bacteria according to claim 1, characterized in that: The shaking flask culture conditions in step S1 are 20-30 degrees Celsius, shaking 150-200 rpm, and culturing for 10-24 hours.

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