Edible mushroom composite fermentation cultivation substrate and preparation process thereof

Abstract

The application discloses a kind of edible mushroom composite fermentation cultivation substrate and its preparation process, belong to agricultural biotechnology field;The substrate includes basic nutrient component, pH response modification biochar-nanocellulose compound and rare earth activator;The compound is formed by amino magnetic biochar and phenylboronic acid modified nanocellulose through borate ester bond dynamic crosslinking;The rare earth activator is mesoporous silica nanoparticle loaded with lanthanum ions;The substrate can automatically adjust crosslinking density according to local pH change during mycelium growth, dynamically optimize air permeability and water retention, and simultaneously activate lignocellulose-degrading enzymes through rare earth ions to accelerate nutrient release;The application also provides preparation methods of each component and overall process;The substrate can significantly shorten the mushroom period, improve yield and quality, and is suitable for factory edible mushroom production.

Description

Technical Field

[0001] This invention belongs to the field of agricultural biotechnology and relates to a compound fermentation cultivation substrate for edible fungi and its preparation process. Background Technology

[0002] The physical structure and chemical properties of the substrate for edible mushroom cultivation directly affect mycelial growth, fruiting uniformity, and yield. Traditional substrates, primarily composed of cottonseed hulls, sawdust, and corn cobs, present three main problems: first, it is difficult to balance aeration and water retention; second, water management is inefficient, easily leading to localized waterlogging or drought; and third, the substrate is susceptible to contamination by other microorganisms after sterilization. Existing improvements include adding inert materials such as perlite and vermiculite to improve aeration, or adding polyacrylamide-based water-retaining agents to enhance water retention. However, these methods are merely simple physical mixtures without synergistic effects between components, and the water-retaining agents may leave harmful monomers. Furthermore, the slow degradation rate of lignocellulose is also a bottleneck restricting the fruiting cycle.

[0003] In recent years, biochar and nanocellulose have been explored for matrix modification due to their unique physicochemical properties. The porous structure of biochar helps adsorb nutrients and water, while nanocellulose has a high specific surface area and strong hydrophilicity. However, when the two are directly mixed, they function independently and cannot form a stable three-dimensional network, nor do they possess intelligent responsiveness. On the other hand, rare earth elements have an activating effect on lignin-degrading enzymes such as cellulase and laccase, but free rare earth ions are easily lost and may produce toxicity, requiring a suitable carrier to achieve slow release.

[0004] Therefore, it is necessary to develop a novel cultivation substrate that can dynamically adjust the substrate structure according to the metabolic needs of mycelia and continuously activate enzyme activity. Summary of the Invention

[0005] The purpose of this invention is to provide a compound fermentation cultivation substrate for edible fungi and its preparation process, which solves the problems of fixed structure, inability to self-adjust, and slow degradation of lignocellulose in existing substrates.

[0006] The technical solution adopted in this invention is as follows:

[0007] A compound fermentation cultivation substrate for edible fungi includes basic nutrients, a pH-responsive modified biochar-nanocellulose complex, and a rare earth activator.

[0008] The pH-responsive modified biochar-nanocellulose composite is formed by dynamic cross-linking of aminated magnetic biochar and phenylboronic acid-modified nanocellulose through borate ester bonds.

[0009] The rare earth activator is mesoporous silica nanoparticles loaded with lanthanum ions.

[0010] The complex and the rare earth activator are synergistically distributed in the matrix through electrostatic adsorption and coordination.

[0011] Furthermore, the basic nutrient components include one or more of cottonseed hulls, wheat bran, corn cobs, gypsum, and lime; the amination magnetic biochar has a particle size of 50-200 micrometers and an amino content of 0.5-1.2 mmol / g; the phenylboronic acid-modified nanocellulose has a length of 100-500 nanometers and a phenylboronic acid grafting amount of 0.3-0.8 mmol / g.

[0012] Furthermore, by weight, the amounts of each component are as follows: 80-90 parts of basic nutrients, 6-12 parts of pH-responsive modified biochar-nanocellulose complex, and 0.5-2 parts of rare earth activator.

[0013] Furthermore, the preparation method of the aminated magnetic biochar includes the following steps:

[0014] S1: Pyrolyze plant straw at 400-600℃ under limited oxygen conditions for 1.5-2.5 hours to obtain raw biochar;

[0015] S2: The original biochar is then subjected to an Fe-containing... 3+ / Fe 2+ Magnetic biochar was obtained by co-precipitation magnetization in an alkaline solution.

[0016] S3: The magnetic biochar and γ-aminopropyltriethoxysilane are refluxed in toluene at 80-100°C for 4-6 hours, washed and dried to obtain the aminated magnetic biochar.

[0017] Furthermore, the preparation method of the phenylboronic acid-modified nanocellulose includes the following steps:

[0018] S1: Natural cellulose fibers were oxidized by TEMPO / NaBr / NaClO and then homogenized under high pressure to obtain carboxylated nanocellulose;

[0019] S2: The carboxylated nanocellulose and 4-carboxyphenylboronic acid were reacted in an aqueous solution at pH 5.5-6.5 for 2-4 hours under EDC / NHS activation, followed by dialyzing and lyophilization to obtain the phenylboronic acid-modified nanocellulose.

[0020] Furthermore, the preparation method of the pH-responsive modified biochar-nanocellulose composite includes the following steps:

[0021] S1: The aminated magnetic biochar and the phenylboronic acid modified nanocellulose are dispersed in a borate buffer solution at a mass ratio of 1:(0.5-1.5) and ultrasonically treated for 10-20 minutes.

[0022] S2: Stir the reaction at 25-35℃ for 1-3 hours to dynamically crosslink the amino group and phenylboronic acid through borate ester bonds. Then, perform magnetic separation, washing, and drying to obtain the complex.

[0023] Furthermore, the preparation method of the rare earth activator includes the following steps:

[0024] S1: Mesoporous silica nanoparticles (pore size 2-5 nm) are dispersed in an ethanol solution containing La(NO3)3. 3+ The mass ratio of SiO2 to SiO2 is 1:(5-10);

[0025] S2: Stir and adsorb at 60℃~80℃ for 4~6 hours, centrifuge, wash, dry, and calcine at 500℃~600℃ for 2~3 hours to obtain the mesoporous silica nanoparticles loaded with lanthanum ions.

[0026] Furthermore, it includes the following steps:

[0027] S1: Pre-wet the basic nutrients and adjust the moisture content to 55%-65%;

[0028] S2: Disperse the pH-responsive modified biochar-nanocellulose composite and the rare earth activator separately in water, mix them after forming a suspension, adjust the pH to 6.5-7.5, let stand for 10-30 minutes to form a pre-crosslinked gel network;

[0029] S3: Mix the pre-crosslinked gel network obtained in S2 with the basic nutrients obtained in S1 evenly, and carry out pile fermentation. The fermentation temperature is 55-65℃ and the time is 48-72 hours. During the process, the pile is turned over 2-3 times.

[0030] S4: Pack the fermented material into bags or bottles, sterilize at 121℃ and 0.1~0.15MPa for 2~3 hours, and inoculate with edible fungi spawn after cooling.

[0031] Furthermore, in step S2, the pH of the pre-crosslinked gel network is adjusted using a 0.1 mol / L sodium hydroxide or hydrochloric acid solution, and the standing temperature is controlled at 20-30°C.

[0032] Furthermore, during the stacking fermentation process in step S3, when the pH of the material drops below 5.5, it automatically triggers the partial breakage of the borate ester bonds in the complex, releasing cross-linking sites to increase porosity and achieve dynamic regulation of aeration.

[0033] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0034] 1. A compound fermentation cultivation substrate for edible fungi and its preparation process, wherein a pH-responsive network is constructed through dynamic borate ester bonds; mycelial metabolism produces acid, causing a local pH decrease, partial hydrolysis of borate ester bonds, making the network looser, increasing porosity, and improving aeration; when the pH rises, the bonds reform, the network tightens, and water retention is restored; this self-regulating ability keeps the substrate in an optimal physical state at all times.

[0035] 2. In this invention, rare earth lanthanum ions are released slowly through mesoporous silica, continuously activating cellulase and laccase, thereby increasing the degradation rate of lignocellulose by more than 40%, releasing nutrients more fully, shortening the fruiting cycle by 6-8 days, and increasing yield by 20%-25%.

[0036] 3. In this invention, the aminated magnetic biochar itself carries a positive charge, which can adsorb negatively charged bacterial spores. At the same time, rare earth ions also have antibacterial effects. The two work together to reduce the pollution rate to below 2%. Attached Figure Description

[0037] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort, wherein:

[0038] Figure 1 This is a flowchart of the preparation process of the present invention. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only for explaining the invention and are not intended to limit the invention; that is, the described embodiments are merely some embodiments of the invention, and not all embodiments. The components of the embodiments of the invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0040] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0041] It should be noted that relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0042] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0043] Example 1

[0044] like Figure 1 As shown in the preferred embodiment of the present invention, a preparation process for a composite fermentation cultivation substrate for edible fungi includes the following steps:

[0045] (I) Preparation of Aminated Magnetic Biochar

[0046] S1: Take corn stalks, crush them to 20-40 mesh, place them in a tube furnace, and pyrolyze them at 500℃ under nitrogen protection for 2 hours to obtain raw biochar with a yield of about 35%.

[0047] S2: The raw biochar was soaked in a mixed solution of FeCl3·6H2O and FeSO4·7H2O (Fe 3+ Fe 2+ The mixture was prepared with a molar ratio of 2:1 and a solid-liquid ratio of 1:10 (g / mL). The pH was adjusted to 10 with 1 mol / L NaOH and stirred at 25°C for 1 hour. After magnetic separation, the mixture was washed with deionized water until neutral and dried at 60°C for 12 hours to obtain magnetic biochar with a magnetic saturation strength of approximately 45 emu / g.

[0048] S3: Magnetic biochar was dispersed in toluene (solid-liquid ratio 1g:20mL), and γ-aminopropyltriethoxysilane (KH-550) was added at a mass ratio of magnetic biochar:KH-550 = 1:0.6. The mixture was refluxed at 90℃ for 5 hours. After the reaction, the mixture was magnetically separated and washed three times each with toluene, ethanol, and deionized water. The mixture was then vacuum dried at 50℃ for 8 hours to obtain aminated magnetic biochar. Elemental analysis showed that the surface amino content was 0.85 mmol / g.

[0049] (II) Preparation of phenylboronic acid-modified nanocellulose

[0050] S1: Take bleached softwood pulp board, crush it, and disperse it in deionized water to prepare a 2% (w / v) suspension. Add TEMPO (0.016 g / g fiber) and NaBr (0.1 g / g fiber), and slowly add NaClO solution (10 mmol / g fiber). Maintain the pH at 10.5 with 0.5 mol / L NaOH and react at 25°C for 2 hours. After the reaction is complete, terminate with anhydrous ethanol, filter and wash until neutral to obtain oxidized cellulose. Prepare a 1% (w / v) suspension of oxidized cellulose and process it five times under 1000 bar pressure using an APV-2000 high-pressure homogenizer to obtain a carboxylated nanocellulose suspension with an average length of about 200 nm and a diameter of about 10 nm.

[0051] S2: Take a suspension of carboxylated cellulose nanoparticles (solid content 1g), add 4-carboxyphenylboronic acid (0.5g), EDC (0.8g) and NHS (0.4g), adjust the pH to 6.0 with 0.1mol / L MES buffer, and react at 25℃ for 3 hours; after the reaction, dialyze in deionized water for 48 hours using a dialysis bag (molecular weight cutoff 14000Da), changing the water every 12 hours; freeze-dry to obtain phenylboronic acid modified cellulose nanoparticles, and determine the phenylboronic acid grafting amount to be 0.56 mmol / g by UV-Vis spectroscopy;

[0052] (III) Preparation of pH-responsive modified biochar-cellulose nanocomposite

[0053] 1 g of aminated magnetic biochar and 0.8 g of phenylboronic acid-modified nanocellulose were dispersed in 50 mL of borate buffer solution at pH 8.5, sonicated for 15 minutes, and then stirred at 30 °C for 2 hours. After the reaction, the mixture was magnetically separated, washed three times with deionized water, and vacuum dried at 40 °C for 6 hours to obtain the complex. The infrared spectrum was observed at 1340 cm⁻¹. -1 The presence of a BOC characteristic peak confirms the formation of a borate ester bond;

[0054] (iv) Preparation of rare earth activators

[0055] Mesoporous silica nanoparticles (pore size 3 nm, specific surface area 600 m²) were used. 2 1 g of lanthanum ions was dispersed in 50 mL of anhydrous ethanol containing 0.2 g of La(NO3)3·6H2O, and the mixture was stirred and adsorbed at 70 °C for 5 hours. The solid was collected by centrifugation, washed twice with ethanol, dried at 60 °C, and then calcined in a muffle furnace at 550 °C for 2 hours to obtain mesoporous silica nanoparticles loaded with lanthanum ions. Inductively coupled plasma atomic emission spectrometry (ICP-OES) determined that the lanthanum loading was 3.8% (mass fraction).

[0056] (v) Matrix preparation

[0057] Basic nutritional components: 75 parts cottonseed hulls, 15 parts wheat bran, 5 parts corn cobs, 2 parts gypsum, 1 part lime (total 98 parts, adjusted for moisture content); based on a total of 100 parts, the actual weighed components are: 87 parts basic nutritional components, 10 parts complex, and 1 part rare earth activator; the preparation method is as follows:

[0058] S1: Mix the basic nutrients evenly, spray with deionized water to pre-wet, adjust the moisture content to 60% (w / w), and let stand for 2 hours to allow the moisture to penetrate evenly.

[0059] S2: Disperse the complex and rare earth activator separately in an appropriate amount of deionized water (2% w / v for both), sonicate for 10 minutes, then mix the two, adjust the pH to 7.0 with 0.1 mol / L NaOH, and let stand at 25°C for 20 minutes to form a pre-crosslinked gel network;

[0060] S3: Add the pre-crosslinked gel network and pre-wetted basic nutrients into a double helix mixer and mix at 30 rpm for 15 minutes until the appearance is uniform. Then transfer the mixture to a fermentation tank, pile it up to a height of 30 cm, cover it with plastic film to keep it warm and moist, and ferment it at 60℃ for 60 hours. During this period, turn the pile once every 24 hours (twice in total) and control the material temperature to not exceed 65℃. Monitor the pH during the fermentation process. At the 36th hour, the pH dropped to 5.3 and the fluffiness of the material was observed to increase.

[0061] S4: After fermentation, pack the material into polypropylene plastic bags (17×33cm, 0.05mm thick), with 1.2kg of material per bag; place them in an autoclave and sterilize at 121℃ and 0.12MPa for 2.5 hours, then allow them to cool naturally to below 25℃ to obtain the substrate. Inoculate the substrate with liquid spawn of king oyster mushroom (10% v / w) in a sterile operating table, seal the substrate, and transfer it to the cultivation room.

[0062] Example 2

[0063] This embodiment is basically the same as Embodiment 1, except that the component ratio is as follows: 90 parts of basic nutrients, 6 parts of complex, and 0.5 parts of rare earth activator. The other steps and parameters are exactly the same.

[0064] Example 3

[0065] This embodiment is basically the same as Embodiment 1, except for the component ratio: 82 parts basic nutrients, 12 parts complex, and 2 parts rare earth activator. The remaining steps and parameters are exactly the same.

[0066] Comparative Example 1

[0067] The traditional cultivation substrate formula was used: 78 parts cottonseed hulls, 18 parts wheat bran, 2 parts gypsum, and 1 part lime (totaling 99 parts, adjusted to 100 parts with water). No complex or rare earth activator was added. The remaining steps (pre-wetting, composting and fermentation, sterilization and inoculation) were the same as in Example 1.

[0068] Comparative Example 2

[0069] Matrix composition: 87 parts basic nutrients, 1 part rare earth activator (no complex), the remaining steps are the same as in Example 1.

[0070] Comparative Example 3

[0071] Matrix composition: 87 parts basic nutrients, 10 parts complex (without rare earth activator), and the remaining steps are the same as in Example 1.

[0072] Comparative Example 4

[0073] The composite was replaced with equal amounts of physically mixed raw biochar (pyrolyzed at 500°C, unmagnetized and unaminated) and unmodified nanocellulose (obtained by high-pressure homogenization only); the rare earth activator was replaced with an equal amount of unloaded mesoporous silica, and the remaining steps were the same as in Example 1.

[0074] Comparative Example 5

[0075] The complex was replaced with a permanent biochar-nanocellulose complex (irreversible crosslinking) prepared by chemical crosslinking with glutaraldehyde, and all other conditions were the same as in Example 1. This comparative example was used to verify the superiority of dynamic covalent bonds.

[0076] Experimental Example 1

[0077] Experimental objective: To evaluate the aeration, water retention capacity, and pH responsiveness of different substrates.

[0078] Test method: Bulk density and porosity determination: Refer to LY / T 1237-1999 ring sampler method; take a volume of 100 cm³. 3 The ring cutter is weighed W1; it is filled with air-dried substrate (dried at 105℃ to constant weight) and weighed W2; the ring cutter is immersed in water for 24 hours until saturated, removed and dried, and weighed W3; then dried at 105℃ to constant weight and weighed W4; calculate:

[0079] bulk density (g / cm³) 3 ) = (W2-W1) / 100;

[0080] Total porosity (%) = (W3-W4) / (W2-W1)×100;

[0081] Ventilation porosity (%) = (W3-W2) / (W2-W1)×100;

[0082] Water-holding porosity (%) = Total porosity - Aeration porosity;

[0083] Maximum water holding capacity determination: Refer to NY / T 1121.22-2010, take 50g of air-dried substrate, put it into a funnel with filter paper at the bottom, slowly add water until saturated, let it stand for 2 hours and weigh it, calculate the maximum water holding capacity (%) = (saturated weight - dry weight) / dry weight × 100;

[0084] pH responsiveness test: Take 10g of each group of matrix samples, put them into a 100mL beaker, add 50mL of pH 5.0 citrate buffer (simulating the acid-producing environment of mycelial metabolism), let stand for 30 minutes, take them out, measure the aeration porosity again, and calculate the rate of change.

[0085] Experimental results: Each sample was tested in triplicate. The results are expressed as mean ± standard deviation. One-way ANOVA was performed using SPSS 26.0. The significance of the results was determined by Duncan's multiple comparison test (p<0.05). The results are shown in Table 1.

[0086] Table 1. Evaluation results of air permeability, water retention capacity, and pH responsiveness of different substrates.

[0087] Group Bulk density (g / cm³) Total porosity (%) Ventilation porosity (%) Water-holding porosity (%) Maximum water holding capacity (%) Change rate of ventilation porosity after acidification (%) Example 1 0.30±0.02a 79.2±1.1a 29.5±0.7a 49.7±1.0a 188.5±3.2a +12.8±1.5a Example 2 0.33±0.01b 77.0±1.0b 27.2±0.6b 49.8±0.9a 181.2±2.8b +10.5±1.2b Example 3 0.29±0.02a 80.5±1.2c 30.8±0.8c 49.7±1.1a 192.6±3.5c +14.2±1.6c Comparative Example 1 0.41±0.03c 68.2±1.4d 18.0±0.6d 50.2±1.2a 144.8±3.8d +0.5±0.3d Comparative Example 2 0.37±0.02d 72.5±1.1e 23.1±0.7e 49.4±1.0a 165.3±3.0e +1.2±0.4d Comparative Example 3 0.35±0.02e 75.3±1.2f 25.6±0.8f 49.7±1.1a 173.6±3.4f +11.8±1.3a Comparative Example 4 0.38±0.02d 69.5±1.3g 19.2±0.7g 50.3±1.2a 149.5±3.6g +0.8±0.3d Comparative Example 5 0.31±0.02a 78.8±1.1a 28.9±0.7a 49.9±1.0a 186.2±3.1a +1.5±0.5d

[0088] Note: Different letters in the same column indicate significant differences (p<0.05);

[0089] Conclusions: The bulk density of the example group was significantly lower than that of the comparative group, while the total porosity and aeration porosity were significantly higher. Regarding the change rate of aeration porosity after acidification, the example group increased by 10.5%-14.2%, while Comparative Examples 1, 2, 4, and 5 remained almost unchanged (<2%), indicating that only complexes containing dynamic borate ester bonds exhibit pH responsiveness. Although Comparative Example 3 lacked a rare earth activator, the complex was still present, thus retaining responsiveness. Comparative Example 5, using permanent crosslinking, lost its responsiveness, demonstrating that dynamic covalent bonds are key to achieving intelligent regulation.

[0090] Experimental Example 2

[0091] Experimental objective: To evaluate the effects of different substrates on the growth, yield, and resistance to contaminating microorganisms of Pleurotus ostreatus.

[0092] Experimental Methods: Cultivation Management: A factory-style bottle cultivation method was adopted, with each bottle containing 350g (dry weight) of substrate, and 30 replicates per group. After inoculation, the bottles were placed in a culture room at 22℃, 65% humidity, and CO2 concentration <2000ppm for mycelial growth. After the mycelium had fully colonized the bottle, it was transferred to a fruiting room (temperature 16℃, humidity 90%, light 500 lux, 12 hours per day). The time to full colonization of the bottle (days), the time to harvest the first flush of mushrooms (days), the yield per bottle (g), and the percentage of marketable mushrooms (%) were recorded (mushroom length >8cm, cap diameter <5cm were considered acceptable).

[0093] Contamination rate statistics: Starting from the 3rd day after inoculation, the number of bottles infected with contaminating fungi such as *Penicillium* and *Nephrolepis* was observed and recorded daily until the first flush of mushrooms was harvested. Contamination rate (%) = (Number of contaminated bottles / Total number of bottles) × 100;

[0094] Determination of lignocellulose degradation rate: Substrate samples were taken before and after fermentation, and the neutral detergent fiber (NDF) content was determined using the Pantheon detergent fiber analysis method. The degradation rate was calculated as (initial NDF - post-fermentation NDF) / initial NDF × 100%.

[0095] Data statistics: Results are expressed as mean ± standard deviation. One-way ANOVA was used for comparisons between groups. p < 0.05 was considered statistically significant. The results are shown in Table 2.

[0096] Table 2. Evaluation results of the effects of different substrates on the growth, yield, and resistance to contaminating microorganisms of Pleurotus ostreatus.

[0097] Group Time to full mycelial colony formation (days) First flush of mushrooms harvest time (days) Yield per bottle (g) Marketable mushroom yield (%) Pollution rate (%) Lignocellulose degradation rate (%) Example 1 16.8±0.4a 30.2±0.7a 85.6±3.0a 94.5±1.8a 1.5±1.0a 48.2±2.5a Example 2 18.0±0.5b 32.0±0.8b 80.2±3.2b 91.0±2.0b 2.8±1.5ab 43.5±2.2b Example 3 16.2±0.4c 29.5±0.7c 87.8±2.8c 95.2±1.6a 1.2±0.8a 50.1±2.6c Comparative Example 1 23.5±0.8d 38.5±1.2d 66.0±4.0d 78.5±3.0c 13.5±3.5c 28.5±3.0d Comparative Example 2 21.5±0.7e 36.5±1.0e 71.0±3.5e 82.0±2.5d 9.0±2.5d 32.0±2.8e Comparative Example 3 18.5±0.6f 33.0±0.9f 78.5±3.3f 88.5±2.2e 4.0±1.8e 40.5±2.4f Comparative Example 4 22.0±0.7g 37.0±1.1g 69.2±3.9g 81.0±3.0d 10.5±3.0f 30.2±3.1d Comparative Example 5 17.0±0.5a 31.0±0.8a 82.0±3.1h 92.0±1.9b 2.0±1.2a 47.0±2.5a

[0098] Note: Different letters in the same column indicate significant differences (p<0.05).

[0099] in conclusion:

[0100] Mycelial growth rate: The time for mycelia to fully colonize the bottle in the Example group was shortened by 5.5-7.3 days compared to Comparative Example 1, with Example 3 showing the fastest growth (16.2 days). Comparative Example 3 (lacking rare earth elements) was 1.7 days slower than Example 1, indicating that the rare earth activator contributed to accelerating mycelial growth. Although Comparative Example 5 (permanent cross-linking) was also relatively fast, it lacked dynamic regulation, and its later effects were not as good as the Example groups.

[0101] Yield: The yield per bottle in the Example group was 21.5%~33.0% higher than that in Comparative Example 1, with Example 3 having the highest yield (87.8g); the yield of Comparative Example 3 (lacking rare earth) was 78.5g, which was lower than that of Example 1, confirming the synergistic effect of rare earth activator on yield increase;

[0102] The commercial mushroom yield of the example groups was higher than 91%, which was significantly better than that of the comparative group;

[0103] Antibacterial activity: The contamination rate of the Example group was only 1.2%-2.8%, far lower than that of Comparative Example 1 (13.5%); the contamination rate of Comparative Example 3 (lacking rare earth elements) was 4.0%, higher than that of Example 1, indicating that rare earth ions also have antibacterial effects.

[0104] Lignocellulose degradation rate: The degradation rate of the Example group reached 43.5%-50.1%, which was 15-21 percentage points higher than that of Comparative Example 1; the degradation rate of Comparative Example 3 (rare earth deficient) was 40.5%, which was lower than that of Example 1, demonstrating the role of rare earth activating enzyme; the degradation rate of Comparative Example 5 (permanent cross-linking) was 47.0%, which was slightly lower than that of Example 1, possibly because permanent cross-linking limited the enzyme's accessibility to the substrate.

[0105] Comprehensive comparison: Example 1 performs excellently in all indicators and is the best ratio; Example 3 has higher yield but increased cost, making it suitable for the high-end market; the synergistic effect of dynamic borate ester bonds and rare earth activators is the core embodiment of the inventiveness of this invention.

[0106] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, and improvements made by those skilled in the art within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A compound fermentation cultivation substrate for edible fungi, characterized in that: It includes basic nutrients, pH-responsive modified biochar-nanocellulose complex, and rare earth activators; The pH-responsive modified biochar-nanocellulose composite is formed by dynamic cross-linking of aminated magnetic biochar and phenylboronic acid-modified nanocellulose through borate ester bonds. The rare earth activator is mesoporous silica nanoparticles loaded with lanthanum ions. The complex and the rare earth activator are synergistically distributed in the matrix.

2. The edible fungi compound fermentation cultivation substrate according to claim 1, characterized in that, The basic nutrient components include one or more of cottonseed hulls, wheat bran, corn cobs, gypsum, and lime; the amination magnetic biochar has a particle size of 50-200 micrometers and an amino content of 0.5-1.2 mmol / g; the phenylboronic acid modified nanocellulose has a length of 100-500 nanometers and a phenylboronic acid grafting amount of 0.3-0.8 mmol / g.

3. The edible fungi compound fermentation cultivation substrate according to claim 1, characterized in that, The amounts of each component by weight are as follows: 80-90 parts of basic nutrients, 6-12 parts of pH-responsive modified biochar-nanocellulose complex, and 0.5-2 parts of rare earth activator.

4. The edible fungi compound fermentation cultivation substrate according to claim 1, characterized in that, The preparation method of the aminated magnetic biochar includes the following steps: S1: Pyrolyze plant straw at 400-600℃ under limited oxygen conditions for 1.5-2.5 hours to obtain raw biochar; S2: The original biochar is then subjected to an Fe-containing... 3+ / Fe 2+ Co-precipitation magnetization was carried out in an alkaline solution to obtain magnetic biochar; S3: The magnetic biochar and γ-aminopropyltriethoxysilane are refluxed in toluene at 80-100°C for 4-6 hours, washed and dried to obtain the aminated magnetic biochar.

5. The edible fungi compound fermentation cultivation substrate according to claim 1, characterized in that, The preparation method of the phenylboronic acid modified nanocellulose includes the following steps: S1: Natural cellulose fibers were oxidized by TEMPO / NaBr / NaClO and then homogenized under high pressure to obtain carboxylated nanocellulose; S2: The carboxylated nanocellulose and 4-carboxyphenylboronic acid were reacted in an aqueous solution at pH 5.5-6.5 for 2-4 hours under EDC / NHS activation, followed by dialyzing and lyophilization to obtain the phenylboronic acid-modified nanocellulose.

6. The edible fungi compound fermentation cultivation substrate according to claim 1, characterized in that, The preparation method of the pH-responsive modified biochar-nanocellulose composite includes the following steps: S1: The aminated magnetic biochar and the phenylboronic acid modified nanocellulose are dispersed in a borate buffer solution at a mass ratio of 1:(0.5~1.5) and ultrasonically treated for 10-20 minutes; S2: Stir the reaction at 25-35℃ for 1-3 hours to dynamically crosslink the amino group and phenylboronic acid through borate ester bonds. Then, perform magnetic separation, washing, and drying to obtain the complex.

7. The edible fungi compound fermentation cultivation substrate according to claim 1, characterized in that, The preparation method of the rare earth activator includes the following steps: S1: Mesoporous silica nanoparticles are dispersed in an ethanol solution containing La(NO3)3. 3+ The mass ratio of SiO2 to SiO2 is 1:(5~10); S2: Stir and adsorb at 60-80℃ for 4-6 hours, centrifuge, wash, dry, and calcine at 500-600℃ for 2-3 hours to obtain the mesoporous silica nanoparticles loaded with lanthanum ions.

8. A process for preparing the edible fungi compound fermentation cultivation substrate as described in any one of claims 1-7, characterized in that, Includes the following steps: S1: Pre-wet the basic nutrients and adjust the moisture content to 55%-65%; S2: Disperse the pH-responsive modified biochar-nanocellulose composite and the rare earth activator separately in water, mix them after forming a suspension, adjust the pH to 6.5-7.5, let stand for 10-30 minutes to form a pre-crosslinked gel network; S3: Mix the pre-crosslinked gel network obtained in S2 with the basic nutrients obtained in S1 evenly, and carry out pile fermentation. The fermentation temperature is 55-65℃ and the time is 48-72 hours. During the process, the pile is turned over 2-3 times. S4: Pack the fermented material into bags or bottles, sterilize at 121℃ and 0.1~0.15MPa for 2~3 hours, and inoculate with edible fungi spawn after cooling.

9. The preparation process according to claim 8, characterized in that, In step S2, the pH of the pre-crosslinked gel network is adjusted using a 0.1 mol / L sodium hydroxide or hydrochloric acid solution, and the standing temperature is controlled at 20-30℃.

10. The preparation process according to claim 8, characterized in that, During the stacking fermentation process in step S3, when the pH of the material drops below 5.5, it automatically triggers the partial breakage of the borate ester bonds in the complex, releasing cross-linking sites to increase porosity and achieve dynamic regulation of aeration.

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