Preparation method of novel vegetation concrete greening additive AB bacteria

Abstract

The invention relates to the technical field of ecological restoration, in particular to a preparation method of novel vegetation concrete greening additive AB bacteria, which comprises the following steps: step (1) screening and activating double bacteria; (2) preparing an inner core structure; (3) loading double bacteria; (4) coating a shell layer; (5) loading a functional matrix; and (6) preparing the vegetation concrete greening additive AB bacteria. According to the method, a multi-layer and function-synergistic microorganism-seed-carrier composite system is constructed and used for surface concrete attachment of the high steep slope, and a plant-microorganism symbiotic system with physical isolation, chemical buffering and nutrition self-sustaining capacities is actively constructed for plant seeds and functional microorganisms in a strongly alkaline macroscopic environment; and finally, the long-acting ecological stability of the high and steep slope is realized.

Description

Technical Field

[0001] This invention relates to the field of ecological restoration technology, specifically to a method for preparing a novel AB bacteria additive for vegetation concrete greening. Background Technology

[0002] In modern infrastructure construction, especially in projects such as highways, railways, water conservancy projects, and mining, numerous steep artificial rock slopes are often created due to excavation. These slopes typically have an inclination greater than 45 degrees, and their matrix is ​​mostly exposed hard rock or an extremely barren mixture of soil and rock. They lack the soil structure and organic matter necessary for plant growth and have extremely poor water and fertilizer retention capacity, making them highly susceptible to soil erosion, rock weathering and erosion, and even instability and collapse under rainfall, posing a serious threat to project safety and the regional ecological environment. Therefore, effective and sustainable ecological protection and vegetation restoration of these steep slopes has become an important topic in the interdisciplinary field of civil engineering and environmental ecology.

[0003] To address these challenges, engineers have developed vegetated concrete technology. This technology involves mixing various components such as cement, soil, organic matter, water-retaining agents, fertilizers, and plant seeds, and then applying this mixture to the target slope surface using spraying machinery to form a cover layer with a certain thickness and initial strength. In principle, the core advantage of this technology lies in utilizing the hydration reaction of cement-based cementitious materials to form a porous, hardened structure with considerable mechanical strength in a short time. This structure can effectively adhere to steep rock faces like a layer of artificial soil, providing a preliminary physical anchoring platform for plant seeds, and significantly improving the slope's surface erosion resistance and overall stability due to its structural strength. At a specific stage of technological development, the emergence of vegetated concrete technology successfully solved the problem of greening construction on hard slopes where traditional topsoil spraying techniques were difficult to apply, achieving a breakthrough from substrate-free to substrate-based methods, representing a significant advancement in slope greening technology.

[0004] However, with the continuous development of related technologies and the increasingly stringent requirements placed on the long-term ecological functions and biodiversity of ecological restoration projects, the traditional vegetation concrete technology, which uses cement as the core binder, has revealed profound internal contradictions in its pursuit of sustainable ecological restoration due to some inherent characteristics at the principle level. The reason for this lies in the inverse relationship between the mechanical properties and ecological suitability of this technology system. Specifically, cement, as a key binder, produces a large amount of alkaline substances such as calcium hydroxide during its hydration process. This causes the pH value of the newly formed vegetation concrete to rise sharply in the early stages of solidification, typically reaching a strongly alkaline level of 12 to 13. This extremely alkaline environment is fatal to most plant seeds and soil microorganisms. It not only directly inhibits seed germination and root elongation but also deals a devastating blow to the vital microbial communities in the soil ecosystem, making it almost impossible for beneficial microorganisms that perform key ecological functions such as nitrogen fixation, phosphorus and potassium activation, and organic matter decomposition to survive and colonize. Therefore, while traditional vegetated concrete solves the primary problem of physical fixation, it inadvertently creates a more hidden and intractable secondary problem—namely, a biocompatible chemical stress. This stress makes vegetation establishment exceptionally difficult and fragile. Even if the slow-release fertilizer in the mixture initially creates a temporary green landscape, the lack of a healthy microbial-plant root symbiotic system to drive nutrient cycling and soil improvement means the system is essentially a closed system lacking vitality and self-repair capabilities. Once the initial nutrients are depleted, the vegetation rapidly declines, making it difficult to form a stable plant community that can sustain itself long-term. Ultimately, the concrete layer, lacking the support of living roots, will gradually deteriorate under long-term natural weathering and rain erosion, failing to fundamentally achieve permanent ecological stability of the slope.

[0005] Therefore, how to effectively overcome the strong alkaline inhibition effect of cement hydration in vegetation concrete, and while providing necessary early mechanical protection, actively construct a local micro-ecological environment suitable for microbial colonization and plant growth, thereby fundamentally resolving the inherent conflict between the mechanical anchoring function and the long-term ecological restoration function in existing technologies, has become a key challenge and an urgent technical problem for those skilled in the art. Summary of the Invention

[0006] To overcome the above deficiencies, this invention provides a method for preparing AB bacteria, a vegetation concrete greening additive, for steep slopes. By constructing a multi-level, functionally synergistic microbial-seed-carrier composite system for surface concrete attachment on steep slopes, a micro-ecological chamber suitable for life colonization is actively built for plant seeds and functional microorganisms in a strongly alkaline macro-environment. This chamber provides physical isolation, chemical buffering, and nutrient self-sufficiency. Thus, while ensuring the initial physical stability of the slope, it drives the establishment of a healthy, self-sustaining plant-microorganism symbiotic system, ultimately achieving long-term ecological stability of steep slopes.

[0007] A method for preparing a novel AB bacteria additive for vegetation concrete landscaping includes the following steps: Step (1) Screening and activation of two bacteria: Isolate alkali-tolerant (pH 8.0-10.0), acid-producing (oxalic acid yield ≥0.5g / L) fungus B (Penicillium oxalicum PB-2) and acid-tolerant (pH 8.5-12.0), nitrogen-fixing (nitrogen fixation ≥20mg / kg) actinomycete A (Frankiasp. AC-1) from rock crevices on steep slopes or rhizosphere soil of local drought-resistant vegetation, and activate them to the logarithmic phase respectively; Step (2) Core structure preparation: An acidic substance (oxalic acid, mass concentration 5-10%) is mixed with fungus B (total viable count ≥1×10⁻⁶). 8 The mixture (CFU / mL) is adsorbed into a porous carrier (diatomaceous earth: activated carbon = 1:1, particle size 0.1-0.5 mm) to form a core. Step (3) Double bacterial loading: Actinomycete A (total viable count ≥ 1 × 10⁻⁶) is loaded with bacteria. 8 The microorganisms (CFU / mL) are mixed with the core (volume ratio 1:1.8-2.2, specifically the ratio of the volume of the actinomycete A suspension to the pore volume of the porous carrier core. The core purpose of this parameter is to control the spatial distribution density of microorganisms in the carrier pores to achieve effective loading and functional synergy of microorganisms), and loaded into the pores of the porous carrier using a vacuum impregnation method (vacuum degree of -0.08MPa, single impregnation time of 30min) to form a dual-microbial core. Step (4) Shell coating: Sodium alginate solution (molecular weight 80-120kDa, viscosity 500-800mPa·s) and calcium chloride solution (concentration 0.2-0.5mol / L) are mixed at a mass ratio of 1:1.45-0.55, and coated onto the core surface of the double bacteria by vacuum impregnation (vacuum degree -0.08MPa, single impregnation time 30min) to obtain AB bacteria-shell-core-shell particles; Step (5) Functional matrix loading: Mix AB bacteria-shell core-shell particles with functional matrix (peat:coconut coir:vermiculite = 1:1:1, particle size 0.3-0.8mm) at a mass ratio of 1:5-10, and air-dry to a moisture content of 20-30% to obtain AB bacteria-carrier composite particles (total viable count ≥1×10⁻⁶). 6 CFU / g); The shell layer functions as a gel network formed by the cross-linking of sodium alginate and calcium ions, primarily delaying the release of acidic substances (oxalic acid) and microorganisms (fungus B, actinomycetes A), rather than completely isolating the environment; the carrier function is to utilize the porous diatomaceous earth: activated carbon composite medium (specific surface area 5-10 m²) 2 The core-shell particles, weighing approximately 100 g, are used to load microorganisms and oxalic acid. Their porous structure (30%-50% porosity) naturally allows for permeability, enabling ions (such as calcium and hydrogen ions) and small molecules (such as moisture) from the environment to penetrate into the interior. The functional substrate, comprising 40%-50% of the total additive mass, serves as the main body of the composite particles. It is formed by a 1:1:1 blend of peat (fibrous humus), coconut coir (loose and porous), and vermiculite (layered silicate), creating a porous, breathable, and mechanically strong three-dimensional network structure. This structure not only provides a stable load-bearing carrier for the core-shell particles but also forms a micro-ecological chamber within the concrete, preventing the loss of microorganisms due to rainwater erosion or soil disturbance, thus ensuring the survival rate of microorganisms during the initial shell protection stage.

[0008] Step (6) Preparation of AB bacteria as a vegetation concrete greening additive: Select drought-resistant, shallow-rooted plant seeds (Bermudagrass or Bahiagrass, germination rate ≥85%), mix with adhesive (xanthan gum, accounting for 5-10% of seed weight), and then mix with AB bacteria-carrier composite particles at a mass ratio of 1:0.1-0.3. Dry at 40℃ until the moisture content is ≤8% to obtain the AB bacteria as a vegetation concrete greening additive.

[0009] Since this scheme mainly focuses on adjusting the pH of different concrete cycles, it is necessary to first introduce plant seeds that can adapt to this scheme in order to initially cover the area with vegetation, improve the growing environment, and lay the groundwork for subsequent diversified vegetation coverage.

[0010] When using, mix the AB bacteria vegetation concrete greening additive with concrete aggregate, gel network material, coarse fiber, water-retaining agent, and slow-release fertilizer in a specified ratio. This mixture can be used for spraying and covering steep slopes. The mixing ratio, by weight percentage, can be: AB bacteria additive for vegetation, concrete, and landscaping: 30%-40%; Gel network material (sodium alginate): 0.5%-2%; Coarse fiber (sisal fiber: polypropylene fiber = 2:1): 0.8%-1.5%; Water-retaining agent (polyacrylamide): 0.5%-1%; Slow-release fertilizer (NPK=15-15-15): 2%-3%; The remainder is based on the weight of the concrete, where the mass ratio of crushed stone (20-40mm): crushed stone (5-20mm): river sand is 3:2:5. The gel network material, sodium alginate, has a molecular weight of 80-120 kDa and a viscosity (1% aqueous solution, 25℃) of 500-800 mPa·s, ensuring cross-linking with calcium ions in the concrete to form a stable gel network (gel strength ≥ 200 g / cm³). 2 ).

[0011] This scheme employs a stepwise adsorption-shell coating-composite loading process design to ensure precise synergy of each component in time and space. First, fungus B and oxalic acid are loaded, utilizing its acid resistance to survive and produce acid in the initial high pH stage. Then, actinomycete A is loaded to avoid mutual inhibition due to environmental incompatibility. The core is coated using a vacuum impregnation method, ensuring the release of acidic substances and actinomycete A during concrete carbonation (release cycle 30-90 days). The core-shell particles and carrier are mixed at a mass ratio of 1:5-10 and air-dried to a moisture content of 20-30%, ensuring the porous structure of the carrier adsorbs both the fungi and acid while preventing fungal inactivation due to excessive moisture.

[0012] Preferably, in step (1), the activation medium for fungal B (Penicillium oxalicum PB-2) is PDA medium (potato 200g / L, glucose 20g / L, agar 20g / L), and it is cultured in the dark at 28℃ for 5-7 days until the spore concentration is ≥1×10⁻⁶. 7 CFU / g; the activation medium for the actinomycete A (Frankiasp. AC-1) was ISP2 medium (yeast extract 4 g / L, mannitol 10 g / L, K2HPO4 1 g / L, MgSO4·7H2O 0.5 g / L, agar 20 g / L), cultured at 28-30℃ with shaking at 180 rpm for 3-5 days until the bacterial concentration was ≥1×10⁻⁶. 8 CFU / mL.

[0013] Preferably, in step (2), the acidic substance is oxalic acid (mass concentration 5-10%), and the mixing ratio with fungus B is 0.1-0.3g:1mL, and the adsorption time is 2-4h, to ensure that fungus B is uniformly coated in the carrier pores.

[0014] Preferably, in step (3), the volume ratio of actinomycete A to the core is 1:2, and the viable count of actinomycete A in the core after loading is ≥5×10⁻⁶. 7 CFU / g (accounting for 30%-40% of the total viable count of the two bacteria).

[0015] Preferably, in step (4), the vacuum impregnation parameters for shell coating are: sodium alginate solution concentration 1%-3%, calcium chloride solution concentration 0.2-0.5 mol / L, impregnation time 30 min, and shell thickness controlled by adjusting the number of impregnations (1 time: 50-80 μm, 2 times: 80-120 μm, 3 times: 120-150 μm).

[0016] As a preferred option, in step (5), the functional substrate needs to be pre-passed through a 20-mesh sieve (particle size 0.85-2.0mm) and sterilized by high-pressure steam at 121℃ for 2h; the air-drying conditions are ventilation drying (wind speed 0.5m / s), and the moisture content is controlled at 20-30% (by touch or instrument detection).

[0017] This solution addresses the core challenges of steep slopes, including high pH inhibition, barren rock, and poor water and fertilizer retention. It adopts a phased pH regulation, dual-microbe synergistic growth promotion, and plant-microbe symbiosis as its core theoretical framework. Through core-shell structure design and material process innovation, it achieves full-cycle restoration of slopes, from rapid stabilization to long-term ecological recovery.

[0018] The challenge of ecological restoration of steep slopes stems essentially from the dual contradiction between the highly alkaline environment (pH 12-13) created by hardened concrete and the poor organic matter content (<1%) in rock crevices. After concrete pouring, the cement hydration reaction releases large amounts of calcium and hydroxide ions, causing the pH of the concrete pore fluid to rise to 12-13. This highly alkaline environment directly inhibits microbial activity, such as fungal spore germination rates (<30%) and actinomycete metabolic activity (reduced by more than 50%). It also hinders plant root growth, causing root hair cell dehydration and enzyme inhibition. Without addressing pH regulation, microorganisms cannot colonize, plants struggle to take root, and the slope will remain trapped in a vicious cycle of exposed rock, rainwater erosion, and nutrient loss.

[0019] This scheme addresses the challenge of pH regulation through the slow-release of acidic substances from the core and shell, and the synergistic effect of two bacteria to promote plant growth. The core and shell structure is the core carrier: the outer layer is a sodium alginate gel shell, which initially forms a stable gel through calcium ion cross-linking, resisting high pH environments (the shell remains intact at pH 12.0); the inner layer is a porous carrier (diatomaceous earth and activated carbon, particle size 0.1-0.5 mm), loaded with acid-resistant fungi B (such as Penicillium oxalicum PB-2) and alkali-resistant actinomycetes A (such as Frankiasp. AC-1), as well as acidic substances (such as oxalic acid).

[0020] The initial stage (0-30 days) refers to the period from concrete pouring to carbonation. On steep slopes, the pH level after concrete hardening reaches 12-13, directly inhibiting microbial activity and plant growth. During this time, the functional substrate utilizes the humus from peat and the metal ions from vermiculite to buffer the high pH environment (pH 12.0-13.0), preventing microbial inactivation due to strong alkali. The core-shell structure of the sodium alginate shell acts as a physical barrier, forming a stable gel network through calcium ion cross-linking, resisting the erosion of internal components by the high pH environment. The porous carrier inside the shell carries fungal B and oxalic acid. Fungal B, due to its acid resistance, slowly metabolizes in the initial stage, locally lowering the pH to 10.0-11.0 by secreting oxalic acid (an acidic substance), reserving a weakly alkaline window for the subsequent activation of actinomycete A. During this stage, Actinomycete A is dormant due to high pH inhibition, avoiding direct competition for nutrients with fungus B; the shallow root system (≤20cm) of plant seeds (Bermudagrass / Bahiagrass) initially takes root in the surface rock crevices, reducing rainwater erosion and providing a stable colonization carrier for microorganisms.

[0021] The mid-term (30-90 days) is a critical stage of crust erosion and rapid pH decline. As the concrete is exposed to air, CO2 gradually penetrates and reacts with Ca(OH)2 in the pore fluid. Due to carbonation (Ca(OH)2 + CO2 → CaCO3 + H2O), the pH of the concrete surface gradually drops to 8.5-9.0. The binding force between the crust and calcium ions weakens, and the crust begins to slowly erode and dissolve. At this time, the oxalic acid (acidic substance) preloaded inside the crust and the oxalic acid produced by fungal B metabolism are released together, further lowering the local pH to 8.0-8.5. Actinomycete A is activated and accelerates the dissolution of insoluble phosphorus (Ca-P, Fe-P) in the rock by secreting citric acid (an acidic substance), releasing available phosphorus. At the same time, its nitrogenase activity is awakened, converting nitrogen in the air into a usable nitrogen source. The synergistic effect between fungus B and actinomycete A forms a positive feedback loop: fungus B produces acid to create a suitable environment for actinomycete A, while actinomycete A fixes nitrogen and solubilizes phosphorus to provide a nitrogen source for fungus B. Together, they maintain a dynamic pH balance between 6.5 and 7.5.

[0022] In the later stages (over 90 days), the plant enters a stable phase of synergistic growth between microorganisms and plants. Once a neutral to slightly acidic environment is established, the nitrogen-fixing and phosphorus-solubilizing abilities of actinomycete A and the acid-producing ability of fungus B stabilize. Together, they improve the increase of available phosphorus and nitrogen accumulation in the soil microenvironment. At this time, the shallow root system (≤20cm) of the plant seeds (Bermudagrass / Bahiagrass) has formed a stable cover. The above-ground stems and leaves reduce water evaporation, while the underground roots secrete polysaccharides (such as pectin) and gel networks (sodium alginate) to synergistically enhance soil aggregate structure and improve water and fertilizer retention. Simultaneously, the malic acid and succinic acid exuded by plant roots, along with the oxalic acid from fungus B and the citric acid from actinomycete A, form polybasic organic acids, further dissolving rock nutrients and promoting rhizosphere growth interaction between microorganisms and plants: microorganisms provide nutrients to plants, and plants provide carbon sources for microorganisms (such as polysaccharides in rhizosphere exudates), forming a long-term stable symbiotic relationship between acid, bacteria, and plants.

[0023] This program selects Cynodon dactylon or Paspalum notatum as suitable grass species, whose physiological characteristics are highly synergistic with microbial metabolites. Cynodon dactylon / Paspalum notatum are shallow-rooted plants (root length ≤20cm), enabling them to quickly establish themselves in surface rock crevices in the early stages, reducing rockfall caused by rainwater erosion (erosion resistance ≥70%) and providing a stable colonization carrier for microorganisms. The above-ground parts of the grass cover the soil surface, reducing water evaporation; the underground parts secrete mucopolysaccharides (pectin), which, in synergy with the gel network, enhance soil aggregate structure and improve water and fertilizer retention capacity.

[0024] This solution integrates the functions of adsorption, protection, controlled release, toughening, water retention, and fertilization through a carrier-shell layer combined with a multi-component combination of gel network, coarse fiber, water-retaining agent, and slow-release fertilizer used in the process. 1. The carrier (peat:coconut coir:vermiculite = 1:1:1) provides a porous structure, adsorbing fungi B, actinomycetes A and oxalic acid, while buffering local pH fluctuations through peat (humus) and vermiculite (metal ions).

[0025] 2. The gel shell formed by the cross-linking of the shell (sodium alginate) and calcium ions initially resists high pH environments (the shell is stable at pH 12.0), but later dissolves due to concrete carbonation (pH drops below 8.5) and calcium ion exchange (dissolution rate 0.1-0.3 g / cm³). 2 ·d), to achieve the sequential release of acidic substances and microbial strains.

[0026] 3. The gel network (sodium alginate) cross-links with calcium ions in concrete to form a three-dimensional network structure, filling rock fissures, enhancing the crack resistance of concrete, and fixing carrier particles at the same time.

[0027] 4. The composite of sisal fiber and polypropylene fiber bridges micro-cracks inside the concrete, inhibits crack propagation, and extends the service life of the slope.

[0028] 5. Anionic polyacrylamide (molecular weight 5-10 million, water absorption ratio 100-200 times) absorbs 100-200 times its own weight in water and releases it slowly (water retention rate ≥80% after 28 days), alleviating drought problems caused by uneven rainfall on steep slopes.

[0029] 6. Slow-release fertilizer provides basic nutrients (nitrogen, phosphorus and potassium content ≥45%), avoids the inactivation of microorganisms due to insufficient nutrition in the early stage (fuccus B carbon source demand satisfaction rate ≥90%, actinomycete A nitrogen source demand satisfaction rate ≥85%), and provides long-lasting fertility for plant growth (plant biomass increases by 40%-50%).

[0030] Compared with existing technologies, the advantages of this invention are: 1. This invention creatively constructs a functional microbial additive integrating a spatiotemporal sequential regulation mechanism through a systematic, multi-step preparation method. The core lies in the precise design of a core-shell structure, which achieves spatial isolation and pre-setting of the temporal activation sequence for two microorganisms with complementary functions but different survival requirements. First, using a combination of chemical and biological methods, the strong alkalinity of the cement matrix is ​​actively and continuously neutralized, creating a safe ecological island for the microorganisms and plants. Then, based on this, a key biological nitrogen fixation process is initiated through a controlled sequential activation mechanism, injecting the system with source nutrients. Finally, this microbial system is highly integrated with functional components such as plant seeds, reinforcing fibers, and water-retaining gels, forming a functionally integrated solution.

[0031] 2. This invention not only directly addresses and solves the core technical problem of the conflict between mechanical properties and ecological functions in the background technology, but also elevates vegetation concrete technology from a passive physical covering system to an active ecological engineering system with self-evolution and development potential, providing solid technical support for the long-term, stable and sustainable ecological restoration of steep rock slopes. Detailed Implementation

[0032] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0033] General Implementation Examples

[0034] A method for preparing a novel AB bacteria additive for vegetation concrete landscaping includes the following steps: Step (1) Dual-strain screening and activation: Alkali-tolerant (pH 8.0-10.0), acid-producing (oxalic acid yield ≥0.5 g / L) fungus B (Penicillium oxalicum PB-2) and acid-tolerant (pH 8.5-12.0), nitrogen-fixing (nitrogen fixation ≥20 mg / kg) actinomycete A (Frankia sp. AC-1) were isolated from rock crevices on steep slopes or rhizosphere soil of local drought-resistant vegetation. Both fungi were activated and cultured to the logarithmic growth phase, with a total viable count ≥1×10⁻⁶. 8 CFU / mL; The activation medium for fungal B (Penicillium oxalicum PB-2) was PDA medium (potato 200 g / L, glucose 20 g / L, agar 20 g / L), and cultured in the dark at 28°C for 5-7 days until the spore concentration was ≥1×10⁻⁶. 7 CFU / g; the activation medium for the actinomycete A (Frankiasp. AC-1) was ISP2 medium (yeast extract 4 g / L, mannitol 10 g / L, K2HPO4 1 g / L, MgSO4·7H2O 0.5 g / L, agar 20 g / L), cultured at 28-30℃ with shaking at 180 rpm for 5 days until the bacterial concentration reached ≥1×10⁻⁶ CFU / g. 8 CFU / mL; The actinomycete A and fungus B used in the following examples and comparative examples are all homologous and were prepared through step (1), so they will not be described again. Step (2) Core structure preparation: Mix acidic substance (oxalic acid solution, mass concentration 5-10%) with fungus B, and adsorb it into a porous carrier (diatomaceous earth: activated carbon = 1:1, particle size 0.1-0.5 mm) to form the core; The mixing ratio of oxalic acid solution to fungal B is 0.1-0.3g:1mL, and the adsorption time is 2-4h to ensure that fungal B is uniformly coated in the pores of the carrier. Step (3) Dual-bacterial loading: Actinomycete A and the core are mixed in a volume ratio of 1:1.8-2.2, and loaded into the pores of a porous carrier by vacuum impregnation method with a vacuum degree of -0.08MPa and a single impregnation time of 30min to form a dual-bacterial core; The volume ratio of actinomycete A to the core is 1:2, and the viable count of actinomycete A in the core after loading is ≥5×10⁻⁶. 7 CFU / g (accounting for 30%-40% of the total viable count of the two bacteria) Step (4) Shell coating: Sodium alginate solution (molecular weight 80-120kDa, viscosity 500-800mPa·s) and calcium chloride solution (concentration 0.2-0.5mol / L) are mixed at a mass ratio of 1:1.45-0.55, and coated onto the core surface of the double bacteria by vacuum impregnation (vacuum degree -0.08MPa, single impregnation time 30min) to obtain AB bacteria-shell-core-shell particles; The parameters for the vacuum impregnation method for shell coating are: sodium alginate solution concentration 1%-3%, calcium chloride solution concentration 0.2-0.5 mol / L, impregnation time 30 min, and shell thickness controlled by adjusting the number of impregnations (1 time: 50-80 μm, 2 times: 80-120 μm, 3 times: 120-150 μm). Step (5) Functional matrix loading: Mix AB bacteria-shell core-shell particles with functional matrix (peat:coconut coir:vermiculite = 1:1:1, particle size 0.3-0.8mm) at a mass ratio of 1:5-10, and air-dry to a moisture content of 20-30% to obtain AB bacteria-carrier composite particles (total viable count ≥1×10⁻⁶). 6 CFU / g); The functional substrate needs to be pre-sieved through a 20-mesh sieve (particle size 0.85-2.0mm) and sterilized by high-pressure steam at 121℃ for 2 hours; the air-drying conditions are ventilation drying (wind speed 0.5m / s), and the moisture content is controlled at 20-30% (by touch or instrument detection); Step (6) Preparation of AB bacteria as a vegetation concrete greening additive: Select drought-resistant, shallow-rooted plant seeds (Bermudagrass or Bahiagrass, germination rate ≥85%), mix with adhesive (xanthan gum, accounting for 5-10% of seed weight), and then mix with AB bacteria-carrier composite particles at a mass ratio of 1:0.1-0.3. Dry at 40℃ until the moisture content is ≤8% to obtain the AB bacteria as a vegetation concrete greening additive.

[0035] Example 1

[0036] A method for preparing a novel AB bacteria additive for vegetation concrete landscaping includes the following steps: Step (1) Double-strain screening and activation; Step (2) Core structure preparation: Mix 7.5% oxalic acid solution with fungal B suspension (total viable count 1×10⁻⁶). 8 The mixture of CFU / mL was prepared at a ratio of 0.2g:1mL and adsorbed into a porous carrier (diatomaceous earth: activated carbon = 1:1, particle size 0.3mm) for 3h to form a core.

[0037] Step (3) Double bacterial loading: The suspension of Actinomycete A (total viable count 1×10⁻⁶) is loaded with bacteria. 8The CFU / mL core obtained in step (2) was mixed with the core obtained in step (2) at a volume ratio of 1:2, and loaded by vacuum impregnation (vacuum degree -0.08MPa, time 30min) to obtain a double-bacterial core. After loading, the viable count of Actinobacterium A in the core reached 5×10⁻⁶. 7 CFU / g (accounting for 35% of the total viable count of the two bacteria).

[0038] Step (4) Shell coating: Sodium alginate solution (concentration 2%, molecular weight 100kDa, viscosity 650mPa·s) and calcium chloride solution (concentration 0.3mol / L) are mixed at a mass ratio of 1:0.5, and coated twice by vacuum impregnation method (vacuum degree -0.08MPa, time 30min) to obtain AB bacteria-shell-core-shell particles.

[0039] Step (5) Functional matrix loading: AB bacteria-shell core-shell particles and functional matrix (peat:coconut coir:vermiculite = 1:1:1, particle size 0.5mm) are mixed at a mass ratio of 1:7. The functional matrix is ​​pre-sieved through a 20-mesh sieve and sterilized by high-pressure steam at 121℃ for 2 hours. It is then air-dried (wind speed 0.5m / s) until the moisture content reaches 25%, thus obtaining AB bacteria-carrier composite particles (total viable count 1×10⁻⁶). 6 CFU / g).

[0040] Step (6) Preparation of AB bacteria as a vegetation concrete greening additive: Select bermudagrass seeds (germination rate 88%) and mix with xanthan gum (7% of seed weight), then mix with AB bacteria-carrier composite particles at a mass ratio of 1:0.2, and dry at 40℃ to a moisture content of 7% to obtain the AB bacteria as a vegetation concrete greening additive (each seed carries ≥1×10 4 CFU strains).

[0041] Example 2

[0042] A method for preparing a novel AB bacteria additive for vegetation concrete landscaping includes the following steps: Step (1) Double-strain screening and activation; Step (2) Core structure preparation: Mix 10% oxalic acid solution with fungal B suspension (total viable count 1×10⁻⁶). 8 A mixture of 0.3 g and 1 mL of CFU / mL was adsorbed onto a porous carrier (diatomaceous earth: activated carbon = 1:1, particle size 0.5 mm) for 4 h to form a core. Step (3) Double bacterial loading: The suspension of Actinomycete A (total viable count 1×10⁻⁶) is loaded with bacteria. 8 The CFU / mL core obtained in step (2) was mixed with the core obtained in step (2) at a volume ratio of 1:1.8, and loaded by vacuum impregnation (vacuum degree -0.08MPa, time 30min) to obtain a double-bacterial core. After loading, the viable count of Actinobacterium A in the core reached 5×10⁻⁶. 7CFU / g (accounting for 40% of the total viable count of the two bacteria); Step (4) Shell coating: Sodium alginate solution (concentration 3%, molecular weight 120kDa, viscosity 800mPa·s) and calcium chloride solution (concentration 0.5mol / L) are mixed at a mass ratio of 1:0.45, and the core surface is coated by vacuum impregnation (vacuum degree -0.08MPa, time 30min). The impregnation is repeated 3 times to obtain AB bacteria-shell-core-shell particles; Step (5) Functional matrix loading: AB bacteria-shell core-shell particles and functional matrix (peat:coconut coir:vermiculite = 1:1:1, particle size 0.8 mm) are mixed at a mass ratio of 1:5. The functional matrix is ​​pre-sieved through a 20-mesh sieve and sterilized by high-pressure steam at 121℃ for 2 hours. It is then air-dried (wind speed 0.5 m / s) until the moisture content reaches 30%, thus obtaining AB bacteria-carrier composite particles (total viable count 1×10⁻⁶). 6 CFU / g); Step (6) Preparation of AB bacteria as a vegetation concrete greening additive: Select Bahia grass seeds (germination rate 85%) and mix them with xanthan gum (adhesive accounting for 10% of seed weight), then mix them with AB bacteria-carrier composite particles at a mass ratio of 1:0.3, and dry them at 40℃ to a moisture content of 6% to obtain the AB bacteria as a vegetation concrete greening additive (each seed carries ≥1×10 4 CFU strains).

[0043] Example 3

[0044] A method for preparing a novel AB bacteria additive for vegetation concrete landscaping includes the following steps: Step (1) Double-strain screening and activation; Step (2) Core structure preparation: Mix 5% oxalic acid solution with fungal B suspension (total viable count 1×10⁻⁶). 8 A mixture of 0.1 g and 1 mL of CFU / mL was adsorbed onto a porous carrier (diatomaceous earth: activated carbon = 1:1, particle size 0.1 mm) for 2 h to form a core. Step (3) Double bacterial loading: The suspension of Actinomycete A (total viable count 1×10⁻⁶) is loaded with bacteria. 8 The CFU / mL core obtained in step (2) was mixed with the core obtained in step (2) at a volume ratio of 1:2.2, and loaded by vacuum impregnation (vacuum degree -0.08MPa, time 30min) to obtain a double-bacterial core. After loading, the viable count of Actinobacterium A in the core reached 5×10⁻⁶. 7 CFU / g (accounting for 30% of the total viable count of the two bacteria); Step (4) Shell coating: Sodium alginate solution (concentration 1%, molecular weight 80kDa, viscosity 500mPa·s) and calcium chloride solution (concentration 0.2mol / L) are mixed at a mass ratio of 1:0.55, and the core surface is coated by vacuum impregnation (vacuum degree -0.08MPa, time 30min). The impregnation is repeated once to obtain AB bacteria-shell-core-shell particles; Step (5) Functional matrix loading: AB bacteria-shell core-shell particles and functional matrix (peat:coconut coir:vermiculite = 1:1:1, particle size 0.3 mm) are mixed at a mass ratio of 1:10. The functional matrix is ​​pre-sieved through a 20-mesh sieve and sterilized by high-pressure steam at 121℃ for 2 hours. It is then air-dried (wind speed 0.5 m / s) until the moisture content reaches 20%, thus obtaining AB bacteria-carrier composite particles (total viable count 1×10⁻⁶). 6 CFU / g); Step (6) Preparation of AB bacteria as a vegetation concrete greening additive: Select bermudagrass seeds (germination rate 85%) and mix with xanthan gum (5% of seed weight), then mix with AB bacteria-carrier composite particles at a mass ratio of 1:0.1, and dry at 40℃ to a moisture content of 8% to obtain the AB bacteria as a vegetation concrete greening additive (each seed carries ≥1×10 4 CFU strains).

[0045] Comparative Example 1

[0046] The difference from Example 1 is that the activated bacteria were directly introduced without loading or coating: A method for preparing a novel AB bacteria additive for vegetation concrete landscaping includes the following steps: Step (1) Double bacterial screening and activation: Same as step (1) in Example 1; Step (2) Core-shell structure preparation: Fungal B loading was omitted, and only 7.5% oxalic acid solution was adsorbed into a porous carrier (diatomaceous earth: activated carbon = 1:1, particle size 0.3 mm) for 3 h; Step (3) Double bacterial loading: omitted; Step (4) Shell coating: Same as step (4) in Example 1 to obtain core-shell particles containing only oxalic acid; Step (5) Functional substrate loading: Same as step (5) in Example 1; Step (6) Preparation of vegetation concrete greening additive AB bacteria: Activated fungus B (1×10 8 CFU / mL) and Actinomyces A (1×10⁻⁶) 8 Mix CFU / mL of the mixture at a volume ratio of 2:1, then mix it with xanthan gum (7% of the seed mass) and Bermuda grass seeds, and finally mix it with AB bacteria-carrier composite particles at a mass ratio of 1:0.2. Dry the mixture at 40℃ until the moisture content is 7%.

[0047] Comparative Example 2

[0048] The difference from Example 1 is that only Actinomycete A is used: A method for preparing a novel AB bacteria additive for vegetation concrete landscaping includes the following steps: Step (1) Dual-strain screening and activation: Only actinomycete A is activated (same as in Example 1), fungus B is not added; Step (2) Core-shell structure preparation: Only 7.5% oxalic acid solution was adsorbed onto the carrier (without fungus B); Step (3) Double bacterial loading: Load only Actinomycete A (5 × 10⁻⁶ viable bacteria) 7 CFU / g).

[0049] Steps (4)-(6): Same as in Example 1.

[0050] Comparative Example 3

[0051] The difference from Example 1 is that only fungus B is used: A method for preparing a novel AB bacteria additive for vegetation concrete landscaping includes the following steps: Step (1) Dual-strain screening and activation: Only fungus B is activated (same as in Example 1), and actinomycete A is not added.

[0052] Step (2) Preparation of core-shell structure: Same as step (2) in Example 1 (containing fungus B and oxalic acid).

[0053] Step (3) Double bacterial loading: Actinomycete A loading is omitted.

[0054] Steps (4)-(6): Same as in Example 1.

[0055] Comparative Example 4

[0056] The difference from Example 1 is that no functional substrate was added: A method for preparing a novel AB bacteria additive for vegetation concrete landscaping includes the following steps: Steps (1)-(4): Same as in Example 1.

[0057] Step (5) Functional matrix loading: The core-shell particles were directly air-dried (without being mixed with the functional matrix), with a moisture content of 25%, to obtain AB bacteria-core-shell particles (total viable count 1×10⁻⁶). 6 CFU / g).

[0058] Step (6) The vegetation concrete greening additive AB bacteria is made: AB bacteria-core shell particles replace AB bacteria-carrier composite particles, and the rest is the same as in Example 1.

[0059] Comparative Example 5

[0060] The difference from Example 1 is that there is no shell coating: A method for preparing a novel AB bacteria additive for vegetation concrete landscaping includes the following steps: Steps (1)-(3): Same as in Example 1.

[0061] Step (4) Shell covering: omitted, directly obtaining the uncovered kernel.

[0062] Step (5) Functional matrix loading: The uncoated core is mixed with the functional matrix to obtain AB bacteria-carrier composite particles (total viable bacteria count 1×10⁻⁶). 6 CFU / g).

[0063] Step (6): Same as in Example 1.

[0064] Detection: 1. Sample plot selection Six sets of comparative plots were selected: Experimental groups 1-3: Vegetated concrete slopes sprayed with the AB bacteria vegetation additive prepared in Examples 1-3 above (each group area 100m²). 2 ); Control groups 1-5: Sprayed with the vegetation concrete greening additive AB bacteria prepared in the above comparative examples 1-5 (slope and rock type were the same as the experimental groups, with an area of ​​100m² per group). 2 ); Control group 3: Untreated bare rock slope (same area, 100m²) 2 ); Each sample plot was set up with three test areas along the slope: upper, middle, and lower. Each slope was replicated three times.

[0065] 2. Vegetation quadrat sampling

[0066] Shrub quadrats: 5m × 5m quadrats were used, with 3 quadrats set up diagonally in each testing area. Records were collected. Plant species (shrub, herb), number of plants, average height, basal diameter (shrub); Vegetation cover (using a combination of visual estimation and grid method, with an accuracy of ±5%). Herbaceous quadrats: Three 1m×1m herbaceous quadrats are set up along the diagonal within each shrub quadrat, and the species, number of plants, average height, and cover of herbaceous plants are recorded. Spray painting operation: When using, mix the AB bacteria vegetation concrete greening additive with concrete aggregate, gel network material, coarse fiber, water-retaining agent, and slow-release fertilizer in a specified ratio. This mixture can be used for spraying and covering steep slopes. The mixing ratio, by weight percentage, can be: AB bacteria additive for vegetation, concrete, and landscaping: 35%; Gel network material (sodium alginate): 1.0%; Coarse fiber (sisal fiber: polypropylene fiber = 2:1): 1.2%; Water-retaining agent (polyacrylamide): 0.8%; Slow-release fertilizer (NPK=15-15-15): 2.5%; The remainder is based on the weight of the concrete, where the mass ratio of crushed stone (20-40mm): crushed stone (5-20mm): river sand is 3:2:5. The gel network material, sodium alginate, has a molecular weight of 80-120 kDa and a viscosity (1% aqueous solution, 25℃) of 500-800 mPa·s, ensuring cross-linking with calcium ions in the concrete to form a stable gel network (gel strength ≥ 200 g / cm³). 2 ).

[0067] Based on the phased characteristics of the additive's effect, the following detection time points were set: Initial stage: 15 days and 30 days after additive spraying (concrete curing period, focus on monitoring pH buffer and microbial survival); Mid-term: 60 days and 90 days (crust erosion and pH decline period, with a focus on monitoring vegetation germination and nutrient release); Later stages: 180 days and 360 days (ecological stability period, with a focus on monitoring community diversity and soil fertility).

[0068] 3. Soil / substrate sampling

[0069] Sampling depth: 0-10cm (surface substrate, main distribution layer of plant roots), 10-20cm (deep substrate). Sampling method: A five-point diagonal sampling method was used for each testing area. After removing surface debris, a ring cutter (100cm) was used. 3 Take undisturbed soil samples (to measure bulk density and porosity), and at the same time take mixed soil samples (each ≥500g), put them into self-sealing bags, label them and bring them back to the laboratory (store at 4℃ and process within 24 hours).

[0070] 4. Vegetation growth indicators

[0071] Plant biomass: Harvest the above-ground parts (stems and leaves) and underground parts (roots) in a 1m×1m plot, kill the green at 105℃ and dry at 70℃ to constant weight, and weigh (accuracy ±0.01g). Seed germination rate: Select dominant plant seeds (such as Bermuda grass and Bahia grass) in the sample plot and determine them by laboratory culture method (25℃, 12h light / 12h dark, repeated 3 times, calculate germination rate after 7 days).

[0072] 5. Physicochemical properties of soil / substrate

[0073] See Table 1.

[0074] Table 1 Physicochemical Properties of Soil / Substrate

[0075] 6. Microbial activity indicators

[0076] Total viable count: Plate count method (using nutrient agar medium, incubated at 30℃ for 48h, counting unit: CFU / g); Number of functional microorganisms: Fungal B: PDA selective medium (with 50 μg / mL penicillin to inhibit bacteria), incubated at 28°C for 5 days for counting; Actinomycete A: ISP2 selective medium (with 50 μg / mL nystatin to inhibit fungi), incubated at 30℃ for 7 days for counting; Acid production capacity: Oxalic acid content was determined by high performance liquid chromatography (HPLC) (sample extracted with 1 mol / L HCl, C18 column, mobile phase 0.1% phosphoric acid water, detection wavelength 210 nm). Nitrogen fixation capacity: The total nitrogen increment in the sample was determined by the Kjeldahl method (compared to the control group, the biological nitrogen fixation capacity was calculated, unit: mg / kg).

[0077] 7. Substrate structural stability index

[0078] Porosity: Dewatering method (measured using a ring sample, calculation formula:) Porosity = 1 (Bulk density / Specific gravity) × 100%, accuracy ±1%; Water-stable aggregate structure: Sieving method (take 100g of air-dried sample, soak in distilled water for 30min, then pass through 2mm and 0.25mm sieves, and calculate the proportion of aggregates >0.25mm) Erosion resistance: Simulated rainfall experiment (rainfall 100 mm / h, slope 30°, erosion rate measured within 30 minutes, unit: g / m³) 2 ) 8. Data processing and result evaluation.

[0079] The test results are shown in Table 2-5.

[0080] Table 2. Vegetation community characteristic detection data at different time periods (180 days)

[0081] Table 3 Dynamic changes in soil physicochemical properties (0-10cm depth)

[0082] The core difference in Comparative Example 4 is the absence of functional substrate. The main function of the functional substrate (peat:coal coir:vermiculite = 1:1:1) is to form micro-ecological chambers through its porous structure, protecting microorganisms from erosion and maintaining the substrate's permeability and aggregate structure. Its impact on soil physicochemical properties is primarily indirect (e.g., indirectly affecting organic matter accumulation and nutrient transformation by protecting microorganisms), rather than directly altering the core mechanisms of physicochemical properties (e.g., pH regulation and nutrient supply). Therefore, Comparative Example 4's data is not listed separately in Table 3, the table of dynamic changes in soil physicochemical properties. Other comparative examples also have missing data in their tables of dynamic changes in soil physicochemical properties, primarily to clearly present the impact of core variables while avoiding data redundancy and improving table readability. For Comparative Example 2 (using only Actinomycete A) and Comparative Example 3 (using only Fungus B), the core difference lies in the effect of a single bacterium versus the synergistic effect of two bacteria. The impact logic is clear, and the 180-day data is sufficient to demonstrate the deficiencies of the single-bacterial group—for example, Comparative Example 2 suffers from a slower pH decrease and insufficient nutrient accumulation due to the lack of acid production from Fungus B, while Comparative Example 3 suffers from nitrogen deficiency due to the lack of nitrogen fixation from Actinomycete A. Their dynamic trends can be inferred from the synergistic effect of the two bacteria in the examples, eliminating the need to repeat the 30-day and 90-day data. The problem with Comparative Example 5 (without shell coating) is concentrated in the early stage. The lack of a shell exposes the microorganisms and oxalic acid directly to a strongly alkaline environment. The 30-day data already clearly reflects its low microbial survival rate and weak acid production capacity. In the middle and late stages, due to the large loss of microorganisms, nutrient accumulation will inevitably lag behind the examples, requiring no further demonstration. Overall, the purpose of the comparative examples is to verify the necessity of a key component, rather than to present the complete cycle. Only data that directly reflects the deficiencies is retained, which highlights the core differences, avoids lengthy tables, ensures clear and readable conclusions, and does not affect the scientific validity and logic of the data.

[0083] Table 4. Microbial activity detection data (90 days)

[0084] Table 5. Substrate structural stability test data (180 days)

[0085] The performance advantage of this embodiment stems from its systematic design and the synergistic effect of multiple components: the core lies in the integrated architecture of dual-bacterial synergy - core-shell protection - functional substrate support. Fungus B (Penicillium acidogeneticum) and actinomycete A (Frankella asiatica) form a positive feedback loop of acid production for pH adjustment - nitrogen fixation and phosphorus solubilization. Initially, fungus B secretes oxalic acid, which binds to the oxalic acid preloaded in the core-shell, gradually reducing the strongly alkaline environment to a weakly alkaline one, thus reserving a window for the activation of actinomycete A. In the middle stage, as the carbonized shell layer of concrete dissolves, actinomycete A is awakened, providing a nitrogen source through nitrogen fixation and releasing available phosphorus through phosphorus solubilization. Together, they adjust the pH... The pH value is stabilized at 6.5-7.5, meeting the needs of plant growth. The sodium alginate shell with a core-shell structure forms a slow-release barrier through calcium ion cross-linking, preventing the inactivation of microorganisms and oxalic acid in the initial stage of strong alkalinity. The three-dimensional network constructed by the functional substrate provides a micro-ecological chamber for the core-shell particles, reducing microbial loss, and also improves water retention, fertilizer retention and air permeability through its porous structure. Combined with the shallow root system of plant seeds (berlebena / Bahia grass) for slope stabilization, the coarse fiber to enhance structural stability, and the continuous supply of water and nutrients by water-retaining agents and slow-release fertilizers, the final result is high vegetation diversity (13-15 species), significant soil nutrient accumulation (organic matter 83.9 g / kg, hydrolyzable nitrogen 660 mg / kg), and strong microbial activity (total viable bacteria count 1.3-1.5 × 10⁻⁶). 6 CFU / g) and excellent substrate erosion resistance (85-95g / m²) 2 ).

[0086] Comparative Example 1, because it did not load or coat the two bacteria, but only directly mixed the activated fungus B and actinomycete A with the seed, resulted in the microorganisms being exposed to the highly alkaline environment of the concrete in its early stages (pH 11.2 after 30 days). Consequently, the survival rate of fungus B and actinomycete A plummeted, with the total viable count reaching only 2.5 × 10⁻⁶. 5 The CFU / g was 1 / 6 of that in Example 1. The synergistic effect of acid production and nitrogen fixation by the two bacteria was disrupted, resulting in insufficient oxalic acid release in the early stages, a slow pH decrease, and a pH that remained at 8.5 after 180 days. The accumulation of organic matter (58.6 g / kg) and hydrolyzable nitrogen (350 mg / kg) was far lower than in Example 1. This was reflected in the vegetation as only 8 species, 65% canopy coverage, and shrub biomass of 30 g / m². 2 Furthermore, the substrate porosity is 32% and the erosion resistance is 210 g / m³. 2Furthermore, structural stability decreased due to insufficient microbial activity. Comparative Example 2 used only Actinomycete A, lacking the continuous acid-producing function of Fungus B, resulting in an oxalic acid content of only 30 mg / kg. This failed to effectively lower the pH to neutral, with a pH of 8.8 after 180 days. Insufficient dissolution of insoluble phosphorus in the rock resulted in a available phosphorus content of 3.2 mg / kg, leading to herbaceous and shrub biomass being only about half that of Example 1. The Gleason index of 2.89 was lower than that of Example 1 (4.62). Additionally, due to the lack of Fungus B to assist in the decomposition of organic matter, total nitrogen and porosity were also at low levels. Comparative Example 3 used only fungus B, without actinomycete A for nitrogen fixation, resulting in zero biological nitrogen fixation and severe nitrogen deficiency. Total nitrogen was 1.1 g / kg, and hydrolyzable nitrogen was 180 mg / kg, insufficient to meet the growth requirements of the shrub. The number of species (7) and the Simpson index (0.48) were the lowest among all groups. Although fungus B produced acid, lowering the pH to 7.0, the lack of nitrogen source limited the synergistic effect between microorganisms and plants. The proportion of water-stable aggregates was 43%, and the erosion resistance was 200 g / m³. 2 It was also weaker than Example 1. Comparative Example 4, without the addition of functional substrates, lacked the three-dimensional network micro-ecological chamber formed by peat, coconut coir, and vermiculite; the microorganisms were easily washed away by rainwater, resulting in a total viable count of 5.0 × 10⁻⁶. 5 With a CFU / g content, a substrate porosity of only 28%, a water-stable agglomerate content of 30%, and an erosion resistance as high as 280 g / m³, the material exhibits excellent performance. 2 The loose structure resulted in poor nutrient retention capacity, with a vegetation cover of 75% and shrub biomass of 60 g / m². 2 All results were inferior to those of Example 1. Comparative Example 5, lacking a shell coating, was directly damaged by the initial strongly alkaline environment (pH 11.8 after 30 days) from fungal B and oxalic acid, resulting in a viable count of only 2.8 × 10⁻⁶ fungi B. 5 CFU / g, oxalic acid 60mg / kg, delayed pH adjustment, insufficient nutrient accumulation after 90 days, organic matter 55.3g / kg, available phosphorus 3.8mg / kg after 180 days, vegetation cover 68%, erosion resistance 250g / m² 2 All indicators were inferior to those of Example 1 due to the lack of shell protection.

Claims

1. A method for preparing a novel AB bacteria additive for vegetation concrete greening, characterized in that, Includes the following steps: Step (1) Screening and activation of two bacteria: Isolate fungi B and actinomycetes A from rock crevices on steep slopes or from the rhizosphere soil of local drought-resistant vegetation, and activate and culture them to the logarithmic phase respectively; Step (2) Core structure preparation: Acidic substances are mixed with fungus B and adsorbed into a porous carrier to form the core; Step (3) Dual-bacterial loading: Actinomycete A and the core are mixed at a volume ratio of 1:1.8-2.2 and loaded onto the pores of a porous carrier by vacuum impregnation to form a dual-bacterial core; Step (4) Shell coating: Sodium alginate solution and calcium chloride solution are mixed and coated onto the core surface of the double bacteria by vacuum impregnation method to obtain AB bacteria-shell-core-shell particles; Step (5) Functional matrix loading: Mix AB bacteria-shell core-shell particles with functional matrix at a mass ratio of 1:5-10, and air dry to a moisture content of 20-30% to obtain AB bacteria-carrier composite particles; Step (6) Preparation of AB bacteria as a vegetation concrete greening additive: Select plant seeds and mix them with 5-10% of their mass of adhesive, then mix them with AB bacteria-carrier composite particles with a plant seed mass ratio of 1:0.1-0.3, and dry them at a low temperature of 40℃ until the moisture content is ≤8% to obtain the AB bacteria as a vegetation concrete greening additive.

2. The preparation method of the novel AB bacteria additive for vegetation concrete greening as described in claim 1, characterized in that, The fungus B is an acid-producing Penicillium, which is alkali-tolerant in the pH range of 8.0-10.0 and has an oxalic acid yield of ≥0.5 g / L.

3. The preparation method of the novel AB bacteria additive for vegetation concrete greening as described in claim 1, characterized in that, The actinomycete A is Frankenstein's bacterium, which is resistant to acid in the pH range of 8.5-12.0 and has a nitrogen fixation capacity of ≥20 mg / kg.

4. The preparation method of the novel AB bacteria additive for vegetation concrete greening as described in claim 1, characterized in that, In step (2), the acidic substance is oxalic acid with a mass concentration of 5-10%, and the total viable bacteria count is ≥1×10⁻⁶. 8 A mixture of fungi B at CFU / mL was adsorbed onto a porous carrier; the porous carrier was a 1:1 ratio of diatomaceous earth to activated carbon.

5. The preparation method of the novel AB bacteria additive for vegetation concrete greening as described in claim 1, characterized in that, The sodium alginate has a molecular weight of 80-120 kDa and a viscosity of 500-800 mPa·s.

6. The preparation method of the novel AB bacteria additive for vegetation concrete greening as described in claim 1, characterized in that, In step (4), the sodium alginate solution and calcium chloride solution are mixed at a mass ratio of 1:1.45-0.55, the sodium alginate solution concentration is 1%-3%, and the calcium chloride solution concentration is 0.2-0.5 mol / L.

7. The preparation method of the novel AB bacteria additive for vegetation concrete greening as described in claim 1, characterized in that, In step (4), the vacuum degree of the vacuum impregnation method is -0.08MPa, and the single impregnation time is 30min.

8. The preparation method of the novel AB bacteria additive for vegetation concrete greening as described in claim 1, characterized in that, The functional substrate is steam sterilized at 121°C for 2 hours; the air-drying conditions are ventilated drying, and the moisture content is controlled at 20-30%.

9. The preparation method of the novel AB bacteria additive for vegetation concrete greening as described in claim 1, characterized in that, The functional substrate is a mixture of peat, coconut coir, and vermiculite with a particle size of 0.3-0.8 mm and a mass ratio of 1:1:

1.

10. The preparation method of the novel AB bacteria additive for vegetation concrete greening as described in claim 1, characterized in that, The plant seeds are Bermuda grass or Bahia grass.

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