Polypeptide-assisted molybdenum disulfide nano-enzyme as well as preparation method and application thereof

Abstract

The invention discloses polypeptide-assisted molybdenum disulfide nano-enzyme as well as a preparation method and application thereof, and relates to the technical field of polymer composite materials. The preparation method comprises the following steps: (1) dissolving a polypeptide polymer with a flexible main chain and a charged side chain in a solvent to prepare a polypeptide polymer solution; (2) mixing molybdenum source molecules, sulfur source molecules and a reducing agent in water to prepare a precursor solution; and (3) adding the polypeptide polymer solution obtained in the step (1) into the precursor solution obtained in the step (2), uniformly mixing, carrying out hydrothermal reaction, cooling, centrifuging, washing and drying to obtain the polypeptide-assisted molybdenum disulfide nano-enzyme. The polypeptide-assisted molybdenum disulfide nano-enzyme shows excellent succinate-like dehydrogenase and peroxidase catalytic activity, can effectively promote algae metabolism and increase the biomass yield, and has good practical value in the fields of biological catalysis, energy conversion and environmental protection.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high polymer composite materials, in particular to a polypeptide-assisted molybdenum disulfide nanoscale enzyme, a preparation method and application thereof. BACKGROUND

[0002] Nanoscale enzyme refers to a series of nanomaterials with the activity of simulating natural enzymes. Due to the special physicochemical properties and nanostructure, the nanoscale enzyme not only has the characteristics of high toughness, low cost and easy recovery of nanomaterials, but also can simulate the catalytic activity of natural enzymes in the physiological environment.

[0003] Molybdenum disulfide (MoS2) has important application value in biological catalysis and energy conversion due to its unique layered structure and enzyme-like properties. The unsaturated atoms exposed on the edge of the layered structure and the defects in the layer provide favorable conditions for catalytic reactions. In addition, MoS2 can exhibit peroxidase-like, catalase-like and oxidase-like properties through structure regulation.

[0004] Unlike oxidases, dehydrogenases can regulate cell NADH / NADPH material flow, drive energy production, synthetic metabolism, antioxidant defense and signal regulation. However, there is no report on MoS2 nanoscale enzyme based on dehydrogenase function. SUMMARY

[0005] In order to solve the technical problems existing in the prior art, the present application provides a polypeptide-assisted molybdenum disulfide nanoscale enzyme, a preparation method and application thereof. The technical solution is as follows:

[0006] A preparation method of a polypeptide-assisted molybdenum disulfide nanoscale enzyme, the preparation method comprising:

[0007] (1) dissolving a polypeptide polymer with a flexible main chain and a charged side chain in a solvent to obtain a polypeptide polymer solution;

[0008] (2) mixing a molybdenum source molecule, a sulfur source molecule and a reducing agent in water to obtain a precursor solution;

[0009] (3) adding the polypeptide polymer solution obtained in step (1) to the precursor solution obtained in step (2), mixing uniformly, then performing hydrothermal reaction, cooling, and then obtaining the polypeptide-assisted molybdenum disulfide nanoscale enzyme through centrifugation, washing and drying.

[0010] Optionally, the polypeptide polymer in step (1) is selected from one of poly-epsilon-lysine, poly-beta-lysine, poly-delta-lysine, poly-arginine, poly-ornithine and poly-histidine, and the molecular weight is 1000-100000 g / mol;

[0011] And / or, the solvent in step (1) is selected from one or more of ethanol, water, N,N-dimethylformamide, dimethyl sulfoxide;

[0012] And / or, the concentration of the polypeptide polymer solution in step (1) is 20-120 g / L.

[0013] Optionally, the molybdenum source molecule in step (2) is selected from one of ammonium molybdate, sodium molybdate, molybdenum acetylacetone, ammonium thiomolybdate;

[0014] And / or, the sulfur source molecule in step (2) is selected from one or more of thiourea, thioacetamide, cysteine, sodium sulfide;

[0015] And / or, the reducing agent in step (2) is selected from one of oxalic acid, ascorbic acid, sodium borohydride.

[0016] Optionally, the molar ratio of the molybdenum source molecule to the reducing agent in step (2) is 1:1 to 1:8;

[0017] And / or, the molar ratio of the molybdenum source molecule to the sulfur source molecule in step (2) is 1:1 to 1:32.

[0018] Optionally, the volume ratio of the polypeptide polymer solution to the precursor solution in step (3) is 1:10 to 1:50;

[0019] And / or, the mass ratio of the polypeptide polymer to the molybdenum element in the molybdenum source molecule in step (3) is 2:1 to 1:2.

[0020] Optionally, the hydrothermal reaction temperature in step (3) is 160-240°C;

[0021] And / or, the reaction time is 16-24 h.

[0022] The polypeptide-assisted molybdenum disulfide nanoszyme prepared by the preparation method.

[0023] Optionally, the polypeptide-assisted molybdenum disulfide nanoszyme has succinate dehydrogenase-like activity and peroxidase activity;

[0024] And / or, in the polypeptide-assisted molybdenum disulfide nanoszyme, the coordination between the ionic group of the polypeptide and the metal ion forms an aggregate, inhibiting the formation of agglomerates, resulting in the polypeptide-assisted molybdenum disulfide nanoszyme having an amorphous phase structure with sulfur vacancies;

[0025] And / or, the polypeptide-assisted molybdenum disulfide nanoszyme is nanospherical with a diameter of 500-600 nm.

[0026] The polypeptide-assisted molybdenum disulfide nanoszyme is used in a method for promoting algal growth or biomass conversion.

[0027] A method for promoting algal growth or biomass conversion, the polypeptide-assisted molybdenum disulfide nanoszyme is co-cultured with algae in a culture medium at a mass ratio of 1:500-1:10.

[0028] And / or, the culture time is 0.5-7 days.

[0029] The technical scheme provided by the embodiment of the present application has at least the following beneficial effects:

[0030] The polypeptide-assisted molybdenum disulfide nanoszyme obtained by the present application has small size and good dispersibility, has succinate dehydrogenase-like and peroxidase activities, and can catalyze the conversion of succinic acid to fumaric acid in the TCA cycle of algal respiration and promote the electron transfer of respiration.

[0031] The method of the present application fixes the distribution of molybdenum elements through the electrostatic interaction between the polypeptide polymer functional groups and molybdenum source ions, limits the accumulation of molybdenum disulfide layers, and at the same time obtains molybdenum disulfide rich in sulfur vacancy defects, and the operation is simple; the polypeptide polymer on the surface improves the dispersibility and biocompatibility of the nanoparticles, exposes more active sites, and improves the contact probability with the substrate. The obtained composite nanoszyme can exhibit excellent succinate dehydrogenase-like and peroxidase activities, and has good application value in the fields of biological catalysis and energy conversion.

[0032] In summary, the method of the present application uses a polypeptide polymer as a template, combines with molybdenum source molecules through coordination, and prepares a molybdenum disulfide composite material with high specific surface area and rich in sulfur vacancies through hydrothermal reaction and one-step reduction. The preparation method provided by the present application has the characteristics of simplicity, high controllability, and low cost, and the obtained nanoparticles exhibit excellent succinate dehydrogenase-like and peroxidase catalytic activities. The polypeptide-assisted molybdenum disulfide nanoszyme can effectively promote algal metabolism and improve biomass yield, and has good practical value in the fields of biological catalysis, energy conversion, and environmental protection. BRIEF DESCRIPTION OF DRAWINGS

[0033] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creating any inventive labor.

[0034] Figure 1 is a scanning electron microscope (SEM) photo of the polypeptide-assisted molybdenum disulfide nanoszyme provided by the embodiment 1 of the present application;

[0035] Figure 2 is an EPR spectrum of the polypeptide-assisted molybdenum disulfide nanoszyme provided in Embodiment 1 of the present application;

[0036] Figure 3 is an ultraviolet-visible spectrum of succinate dehydrogenase enzyme activity detection of the polypeptide-assisted molybdenum disulfide nanoszyme provided in Embodiment 1 of the present application;

[0037] Figure 4 is a fluorescence spectrum of peroxidase enzyme activity detection of the polypeptide-assisted molybdenum disulfide nanoszyme provided in Embodiment 1 of the present application;

[0038] Figure 5 is a columnar graph of protein content of green algae after the polypeptide-assisted molybdenum disulfide nanoszyme provided in Embodiment 1 of the present application is co-cultured with the green algae;

[0039] Figure 6 is a columnar graph of lipid content of green algae after the polypeptide-assisted molybdenum disulfide nanoszyme provided in Embodiment 1 of the present application is co-cultured with the green algae. DETAILED DESCRIPTION

[0040] The technical solutions in the present application will be described below with reference to the drawings.

[0041] The present application aims to overcome the defects of single catalytic performance and poor cycle stability of molybdenum disulfide, and provides a polypeptide-assisted molybdenum disulfide nanoszyme and a preparation method thereof, which can promote algal respiration and increase biomass yield.

[0042] Biological macromolecules are rich in functional groups such as carboxyl, amino, hydroxyl or sulfur-containing groups, which can accurately regulate the morphology and structure of the generated product in a liquid phase system, thereby effectively reducing the particle size and improving the dispersibility. In addition, biological macromolecules can also improve the biocompatibility of the composite material. The present inventors have found that polypeptide polymers, due to their flexible main chain and charged side chain structure, can not only fix metal ions through coordination, but also regulate the size and phase structure of molybdenum disulfide. The present inventors have taken advantage of this feature to prepare molybdenum disulfide with both peroxidase activity and dehydrogenase activity, which has practical value for the application of polymer composites in enzyme-like design and catalysis.

[0043] The technical solution of the present application is to mix polypeptide polymers with precursor solution to fix metal ions through coordination. Then, through hydrothermal reaction, a multi-enzyme activity nanoparticle with good dispersibility and small size can be prepared by one-step reduction. The nanoparticle can be co-cultured with algal cells to effectively exert the enzyme-like activity, thereby improving the biomass yield.

[0044] The technical key point of the method of the application is that a polypeptide polymer is used as a template to combine with a molybdenum source molecule through coordination, and a molybdenum disulfide composite material rich in sulfur vacancies and having a high specific surface area is prepared through hydrothermal reaction and one-step reduction. The polypeptide is used as a soft template, the coordination of the ionic groups of the polypeptide and metal ions forms an aggregate, the Oswald ripening process of the molybdenum disulfide is regulated, and the formation of agglomerates is inhibited, so that the polypeptide-assisted molybdenum disulfide nanoscale enzyme has an amorphous phase structure rich in sulfur vacancies, and these microstructure characteristics endow the polypeptide-assisted molybdenum disulfide nanoscale enzyme with stronger catalytic activity and improve the enzyme-like activity.

[0045] The method of the application controls the volume ratio of the polypeptide polymer solution and the precursor solution, controls the mass ratio of the polypeptide polymer and molybdenum elements, regulates nucleation through the coordination of the ionic groups of the polypeptide polymer and metal ions, reduces the size of the molybdenum disulfide nanoparticles, and at the same time, obtains molybdenum disulfide rich in sulfur vacancy defects. With the assistance of biological macromolecules, molybdenum disulfide nanoparticles exhibiting excellent succinate dehydrogenase-like activity and peroxidase activity are obtained.

[0046] The specific steps of the preparation method of the application are as follows:

[0047] (1) Dissolve a polypeptide polymer having a flexible main chain and charged side chains in a solvent to form a polypeptide polymer solution;

[0048] (2) Mix a molybdenum source molecule, a sulfur source molecule and a reducing agent in water to form a precursor solution;

[0049] (3) Add the polypeptide polymer solution obtained in step (1) to the precursor solution obtained in step (2), mix uniformly, and then transfer to a reaction kettle for one-step hydrothermal reaction. After cooling, centrifugation, washing and drying, a polypeptide-assisted molybdenum disulfide nanoscale enzyme is obtained. The composite nanoscale enzyme has succinate dehydrogenase-like activity and peroxidase activity.

[0050] Preferably, the polypeptide polymer in step (1) is one of poly-epsilon-lysine, poly-beta-lysine, poly-delta-lysine, poly-arginine, poly-ornithine and poly-histidine, and the molecular weight is 1000-100000 g / mol.

[0051] Further preferably, the solvent in step (1) is one or more of ethanol, water, N,N-dimethylformamide and dimethyl sulfoxide.

[0052] Further preferably, the molybdenum source molecule in step (2) is one of ammonium molybdate, sodium molybdate, molybdenum acetylacetone and ammonium thiomolybdate. The sulfur source molecule is one of thiourea, thioacetamide, cysteine and sodium sulfide. The reducing agent is one of oxalic acid, ascorbic acid and sodium borohydride. The molar ratio of the molybdenum source molecule and the reducing agent is 1:1 to 1:8.

[0053] Further preferably, the volume ratio of the polymer solution to the precursor solution in step (3) is 1:10 to 1:50; the mass ratio of the polymer to the molybdenum element in the molybdenum source is 2:1 to 1:2.

[0054] Further preferably, the hydrothermal reaction temperature in step (3) is 160-240℃, and the reaction time is 16-24 h.

[0055] Application of a polypeptide-assisted molybdenum disulfide nanoscale enzyme. The polypeptide-assisted molybdenum disulfide nanoscale enzyme prepared above is co-cultured with algae in a culture medium at a mass ratio of 1:500-1:10. After sufficient action, the growth rate of the algae is significantly promoted, and the respiratory metabolic pathway and biomass conversion of the algae are promoted.

[0056] Further preferably, the number of days of co-culture is 0.5-7 days.

[0057] To make the technical problems, technical solutions and advantages of the present application clearer, specific embodiments will be described in detail below with reference to the drawings.

[0058] Example 1

[0059] (1) 16 mg of polypeptide polymer polylysine (molecular weight 5000-6000 g / mol, available from Sigma-Aldrich (Shanghai) Trading Co., Ltd.) was dissolved in 0.5 mL of dimethyl sulfoxide, and a uniform solution was formed by ultrasonic treatment for 20 minutes to obtain a polypeptide polymer solution.

[0060] (2) 36.3 mg of sodium molybdate dihydrate (available from Shanghai Maikelin Biochemical Technology Co., Ltd.), 35.4 mg of thiourea (available from Shanghai Aldrin Biochemical Technology Co., Ltd.), and 13 mg of oxalic acid (available from Tianjin Xinsen Optod Technology Co., Ltd.) were dissolved in 14.5 mL of deionized water, and a uniform dispersion was obtained after stirring and ultrasonic treatment for 20 minutes to form a precursor solution.

[0061] (3) The polymer solution obtained in step (1) was added to the precursor solution obtained in step (2), and after ultrasonic treatment until the mixture was uniform, it was transferred to a reaction kettle for hydrothermal reaction at 200℃ for 24 h. After cooling, the product was collected and centrifuged at 9000 rpm for 3-4 times, and then freeze-dried for 12 h to obtain a polypeptide polymer-molybdenum disulfide complex, i.e., a polypeptide-assisted molybdenum disulfide nanoscale enzyme. The polypeptide-assisted molybdenum disulfide nanoscale enzyme prepared was photographed to obtain a scanning electron microscope image.

[0062] The powder sample was scanned by a continuous wave electron paramagnetic resonance spectrometer (FA-200) at a frequency of 9.4 GHz to obtain an electron paramagnetic resonance spectrum.

[0063] Performance test:

[0064] The polypeptide-assisted molybdenum disulfide nanoszyme was subjected to succinate dehydrogenase enzyme activity detection, and the test method was as follows: the polypeptide-assisted molybdenum disulfide nanoszyme was subjected to succinate dehydrogenase enzyme activity determination by using an SDH activity detection kit (colorimetric method) (available from Beijing Solabio Technology Co., Ltd.). 100 μL of sample solution with a concentration of 2 mg / mL was added to 1.9 mL of detection reagent, and the change in absorbance of the oxidation-reduction indicator 2,6-dichlorophenol indophenol at a wavelength of 600 nm with time was monitored to evaluate the succinate dehydrogenase enzyme activity of the polypeptide-assisted molybdenum disulfide nanoszyme.

[0065] The polypeptide-assisted molybdenum disulfide nanoszyme was subjected to peroxidase enzyme activity detection, and the test method was as follows: the prepared polypeptide-assisted molybdenum disulfide nanoszyme (2 μg / mL) and hydrogen peroxide (0.1 mM) were added to 1 mL of terephthalic acid (2.5 mM) solution, and the fluorescence spectrum was tested.

[0066] (4) The prepared polypeptide-assisted molybdenum disulfide nanoszyme and green algae were co-cultured in the culture medium at a mass ratio of 1:30 for 7 days. After the culture was completed, the proportion of protein and lipid in the dry cell weight of the green algae was determined, and the method was as follows: the algal cell suspension was centrifuged at 7000 rpm at 4 ℃ for 5 min, washed with deionized water for 3 times, and then subjected to subsequent analysis.

[0067] Protein content analysis: under the same OD 680 condition, 10 mL of algal cells were collected, 0.5 g of quartz sand was added, and the homogenate was ground in an ice bath. The homogenate was centrifuged at 4 ℃ at 13000 g for 5 min, and the supernatant was collected. The collected supernatant was subjected to protein content determination by using a Pierce BCA protein detection kit (available from Thermo Fisher Scientific (China) Co., Ltd.).

[0068] Lipid content analysis: the collected cell precipitate was dried in an oven at 85 ℃ for 12 h, weighed (M1, g), soaked in ether for 16 h, and then extracted by a Soxhlet extractor for 6 h. After drying, the sample weight was re-weighed (M2, g). The fat content was calculated according to the following formula:

[0069] .

[0070] Experimental results:

[0071] The experimental results are shown in Table 1. Figures 1 to 5 .

[0072] Figure 1is a scanning electron microscope (SEM) image of the polypeptide-assisted molybdenum disulfide nanoszyme. According to Figure 1 It can be seen that the composite nanoszyme is nanospherical and has a diameter of about 500-600 nm, is small in size and well dispersed.

[0073] Figure 2 is an EPR spectrum of the polypeptide-assisted molybdenum disulfide nanoszyme. is from Figure 2 It can be seen from that there is a strong signal at g = 2.003, indicating the presence of S vacancies.

[0074] Figure 3 is an ultraviolet-visible spectrum of the succinate dehydrogenase-like enzyme activity detection of the polypeptide-assisted molybdenum disulfide nanoszyme. According to Figure 3 It can be seen that the absorbance value of 2,6-dichlorophenol indophenol gradually decreases over time and is completely catalytically reduced after 30 minutes, completely changing from the blue oxidized state to the colorless hydroquinone-type reduced state, indicating that the polypeptide-assisted molybdenum disulfide nanoszyme has good succinate dehydrogenase-like enzyme activity.

[0075] Figure 4 is a fluorescence spectrum of the peroxidase-like enzyme activity detection of the polypeptide-assisted molybdenum disulfide nanoszyme. According to Figure 4 It can be seen that after 1 hour of incubation, a fluorescence signal can be observed near 425 nm: this signal is derived from the hydroxyl terephthalic acid generated by the oxidation of terephthalic acid by hydroxyl radicals (·OH), and this result indicates that the polypeptide-assisted molybdenum disulfide nanoszyme has excellent peroxidase activity.

[0076] Figure 5 is a column chart of the protein content of green algae after the polypeptide-assisted molybdenum disulfide nanoszyme and green algae were co-cultured. From Figure 5 It can be seen that after co-culturing with the polypeptide-assisted molybdenum disulfide nanoszyme, the proportion of green algae protein to dry cell weight increased by 23.16%, promoting the increase in green algae biomass.

[0077] Figure 6 is a column chart of the lipid content of green algae after the polypeptide-assisted molybdenum disulfide nanoszyme and green algae were co-cultured. From Figure 6 It can be seen that after co-culturing with the polypeptide-assisted molybdenum disulfide nanoszyme, the proportion of green algae lipid to dry cell weight increased by 33.79%, promoting the increase in green algae biomass.

[0078] The above results show that the polypeptide-assisted molybdenum disulfide nanoszyme has excellent succinate dehydrogenase-like enzyme and peroxidase activity, and after co-culturing with green algae, the proportions of green algae protein and lipid to dry cell weight increased by 23.16% and 33.79%, respectively.

[0079] Example 2​

[0080] Steps (1)-(3) are the same as Example 1.

[0081] (4) The polypeptide-assisted molybdenum disulfide nanoszyme prepared above was co-cultured with green algae in a culture medium at a mass ratio of 1:10 for 3 days. The proportion of protein and lipid in dry cell weight of green algae was determined.

[0082] The results show that the proportion of protein and lipid in dry cell weight of green algae has increased by 11.5% and 15.23%, respectively.

[0083] Example 3

[0084] (1) 160 mg of polypeptide polymer polylysine (molecular weight 5000-6000 g / mol, available from Sigma-Aldrich (Shanghai) Trading Co., Ltd.) was dissolved in 1.5 mL of dimethyl sulfoxide, and a uniform solution was formed by ultrasonic treatment for 20 minutes to obtain a polypeptide polymer solution.

[0085] (2) 363 mg of sodium molybdate dihydrate (available from Shanghai Maikelin Biochemical Technology Co., Ltd.), 354 mg of thiourea (available from Shanghai Aladdin Biochemical Technology Co., Ltd.), and 130 mg of oxalic acid (available from Tianjin Xinesi Optoelectronic Technology Co., Ltd.) were dissolved in 13.5 mL of deionized water, and a uniform dispersion was obtained after ultrasonic treatment for 20 minutes to obtain a precursor solution.

[0086] (3) The polymer solution obtained in step (1) was added to the precursor solution obtained in step (2) and mixed uniformly under ultrasonic conditions, then transferred to a reaction kettle, and subjected to hydrothermal reaction at 160°C for 24 h. After cooling, the product was collected and centrifuged at 9000 rpm for 3-4 times, and freeze-dried for 24 h to obtain a polypeptide polymer and molybdenum disulfide complex, i.e., a polypeptide-assisted molybdenum disulfide nanoszyme.

[0087] (4) The polypeptide-assisted molybdenum disulfide nanoszyme prepared above was co-cultured with blue-green algae in a culture medium at a mass ratio of 1:20 for 7 days. The proportion of protein and lipid in dry cell weight of blue-green algae was determined.

[0088] Experimental results:

[0089] The proportion of protein and lipid in dry cell weight of blue-green algae has increased by 5.6% and 13.2%, respectively.

[0090] Example 4

[0091] (1) 48 mg of polypeptide polymer polylysine (molecular weight 5000-6000 g / mol, available from Sigma-Aldrich (Shanghai) Trading Co., Ltd.) was dissolved in 1.5 mL of dimethyl sulfoxide, and a uniform solution was formed by ultrasonic treatment for 20 minutes to obtain a polypeptide polymer solution.

[0092] (2) 108.9 mg of sodium molybdate dihydrate (available from Shanghai Maikelin Biochemical Technology Co., Ltd.), 106.2 mg of thiourea (available from Shanghai Aladdin Biochemical Technology Co., Ltd.), and 39 mg of oxalic acid (available from Tianjin Xinsen Aopted Technology Co., Ltd.) were dissolved in 43.5 mL of deionized water, and a uniform dispersion was obtained after ultrasonic treatment for 20 minutes to obtain a precursor solution.

[0093] (3) The polymer solution obtained in step (1) was added to the precursor solution obtained in step (2) and mixed uniformly under ultrasonic conditions, then transferred to a reaction kettle, and subjected to a hydrothermal reaction at 240°C for 16 h. After cooling, the product was collected and washed 3-4 times by centrifugation at 9000 rpm, and freeze-dried for 24 h to obtain a polypeptide polymer and molybdenum disulfide complex, i.e., a polypeptide-assisted molybdenum disulfide nanoscale enzyme.

[0094] (4) The polypeptide-assisted molybdenum disulfide nanoscale enzyme prepared above was co-cultured with blue-green algae in a culture medium at a mass ratio of 1:20 for 7 days. The proportion of protein and lipid in the dry cell weight of the blue-green algae was determined.

[0095] Experimental results:

[0096] The proportion of protein and lipid in the dry cell weight of the blue-green algae was increased by 15.3% and 27.4%, respectively.

[0097] Example 5

[0098] (1) 34.8 mg of polypeptide polymer polyarginine (molecular weight 5000-15000 g / mol, available from Sigma-Aldrich (Shanghai) Trading Co., Ltd.) was dissolved in 1 mL of deionized water, and a uniform solution was formed by ultrasonic treatment for 20 minutes to obtain a polypeptide polymer solution.

[0099] (2) 72.6 mg of sodium molybdate dihydrate (available from Shanghai Maikelin Biochemical Technology Co., Ltd.), 70.8 mg of thiourea (available from Shanghai Aladdin Biochemical Technology Co., Ltd.), and 26 mg of oxalic acid (available from Tianjin Xinsen Aopted Technology Co., Ltd.) were dissolved in 14 mL of deionized water, and a uniform dispersion was obtained after stirring and ultrasonic treatment for 20 minutes to form a precursor solution.

[0100] (3) The polymer solution obtained in step (1) is added to the precursor solution obtained in step (2), and after ultrasonic mixing until uniform, it is transferred to a reaction kettle for hydrothermal reaction at 240°C for 24 h. After cooling, the product is collected and washed 3-4 times by centrifugation at 9000 rpm, and freeze-dried for 16 h to obtain a polypeptide polymer and molybdenum disulfide complex, i.e., a polypeptide-assisted molybdenum disulfide nanoscale enzyme.

[0101] (4) The polypeptide-assisted molybdenum disulfide nanoscale enzyme prepared above is co-cultured with green algae in a culture medium at a mass ratio of 1:30 for 5 days. The proportion of protein and lipid in the dry cell weight of the green algae is determined.

[0102] Experimental results:

[0103] The proportion of protein and lipid in the dry cell weight of the green algae is increased by 7.8% and 12.6%, respectively.

[0104] Example 6

[0105] (1) 16 mg of polypeptide polymer polylysine (molecular weight 5000-6000 g / mol, available from Sigma-Aldrich (Shanghai) Trading Co., Ltd.) is dissolved in 0.5 mL of dimethyl sulfoxide, and ultrasonic mixing is performed for 20 minutes to form a uniform solution, obtaining a polypeptide polymer solution.

[0106] (2) 26.4 mg of ammonium molybdate tetrahydrate (available from Thermo Fisher Scientific (China) Co., Ltd.), 45 mg of thioacetamide (available from Shanghai Aladdin Biochemical Technology Co., Ltd.), and 13 mg of oxalic acid (available from Tianjin Hensin Optoelectronic Technology Co., Ltd.) are dissolved in 14.5 mL of deionized water, and after stirring and ultrasonic mixing for 20 minutes, they are uniformly dispersed to form a precursor solution.

[0107] (3) The polymer solution obtained in step (1) is added to the precursor solution obtained in step (2), and after ultrasonic mixing until uniform, it is transferred to a reaction kettle for hydrothermal reaction at 180°C for 24 h. After cooling, the product is collected and washed 3-4 times by centrifugation at 9000 rpm, and freeze-dried for 12 h to obtain a polypeptide polymer and molybdenum disulfide complex, i.e., a polypeptide-assisted molybdenum disulfide nanoscale enzyme.

[0108] (4) The polypeptide-assisted molybdenum disulfide nanoscale enzyme prepared above is co-cultured with green algae in a culture medium at a mass ratio of 1:20 for 7 days. The proportion of protein and lipid in the dry cell weight of the green algae is determined.

[0109] Experimental results:

[0110] The proportion of protein and lipid in the dry cell weight of the green algae is increased by 9.8% and 15.9%, respectively.

[0111] Example 7

[0112] (1) 17.4 mg of polypeptide polymer polyarginine (molecular weight 5000-15000 g / mol, available from Sigma-Aldrich (Shanghai) Trading Co., Ltd.) was dissolved in 0.5 mL of dimethyl sulfoxide, and a uniform solution was formed by ultrasonic treatment for 20 minutes to obtain a polypeptide polymer solution.

[0113] (2) 26.4 mg of ammonium molybdate tetrahydrate (available from Thermo Fisher Scientific (China) Co., Ltd.), 48.9 mg of thiourea (available from Shanghai Aladdin Biochemical Technology Co., Ltd.), and 35.2 mg of ascorbic acid (available from Shanghai Aladdin Biochemical Technology Co., Ltd.) were dissolved in 14.5 mL of deionized water, and after stirring and ultrasonic treatment for 20 minutes, a precursor solution was formed.

[0114] (3) The polymer solution obtained in step (1) was added to the precursor solution obtained in step (2), and after ultrasonic treatment until the mixture was uniform, it was transferred to a reaction kettle for hydrothermal reaction at 200°C for 24 h. After cooling, the product was collected and centrifuged at 9000 rpm for 3-4 times, and then freeze-dried for 16 h to obtain a polypeptide polymer and molybdenum disulfide complex, i.e., a polypeptide-assisted molybdenum disulfide nanoscale enzyme.

[0115] (4) The polypeptide-assisted molybdenum disulfide nanoscale enzyme prepared above was co-cultured with green algae in a culture medium at a mass ratio of 1:15 for 7 days. The proportion of protein and lipid in the dry cell weight of the green algae was determined.

[0116] Experimental results:

[0117] The proportion of protein and lipid in the dry cell weight of the green algae was increased by 13.5% and 17.4%, respectively.

[0118] Among them, the scanning electron microscope (SEM) photos, EPR spectra, succinate dehydrogenase enzyme activity, and peroxidase enzyme activity of the polypeptide-assisted molybdenum disulfide nanoscale enzyme of Examples 2 to 7 are the same or similar to those of Example 1, and will not be described one by one.

[0119] The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can easily think of changes or replacements within the technical scope disclosed by the present application, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A method for preparing a polypeptide-assisted molybdenum disulfide nanoszyme, characterized in that, The preparation method comprises: (1) dissolving a polypeptide polymer with a flexible main chain and a charged side chain in a solvent to obtain a polypeptide polymer solution; (2) mixing a molybdenum source molecule, a sulfur source molecule and a reducing agent in water to obtain a precursor solution; (3) adding the polypeptide polymer solution obtained in step (1) into the precursor solution obtained in step (2), mixing uniformly, then performing hydrothermal reaction, and after cooling, obtaining the polypeptide-assisted molybdenum disulfide nanoscale enzyme through centrifugation, washing and drying.

2. The production method according to claim 1, characterized by, The polypeptide polymer in step (1) is selected from one of poly-epsilon-lysine, poly-beta-lysine, poly-delta-lysine, poly-arginine, poly-ornithine and poly-histidine, and the molecular weight is 1000-100000 g / mol; And / or, the solvent in step (1) is selected from one or more of ethanol, water, N,N-dimethylformamide and dimethyl sulfoxide; And / or, the concentration of the polypeptide polymer solution in step (1) is 20-120 g / L.

3. The preparation method according to claim 1, characterized in that, The molybdenum source molecule in step (2) is selected from one of ammonium molybdate, sodium molybdate, molybdenum acetylacetone and ammonium thiomolybdate; And / or, the sulfur source molecule in step (2) is selected from one or more of thiourea, thioacetamide, cysteine and sodium sulfide; And / or, the reducing agent in step (2) is selected from one of oxalic acid, ascorbic acid and sodium borohydride.

4. The method of claim 1, wherein, The molar ratio of the molybdenum source molecule to the reducing agent in step (2) is 1:1 to 1:8; And / or, the molar ratio of the molybdenum source molecule to the sulfur source molecule in step (2) is 1:1 to 1:

32.

5. The preparation method according to claim 1, characterized in that, The volume ratio of the polypeptide polymer solution to the precursor solution in step (3) is 1:10 to 1:50; And / or, the mass ratio of the polypeptide polymer to the molybdenum element in the molybdenum source molecule in step (3) is 2:1 to 1:

2.

6. The method of claim 1, wherein, The hydrothermal reaction temperature in step (3) is 160-240℃; And / or, the reaction time is 16-24 h.

7. The polypeptide-assisted molybdenum disulfide nanoscale enzyme prepared by the preparation method in any one of claims 1-6.

8. The polypeptide-assisted molybdenum disulfide nanoszyme according to claim 7, characterized in that, The polypeptide-assisted molybdenum disulfide nanoscale enzyme has succinate dehydrogenase-like activity and peroxidase activity; And / or, in the polypeptide-assisted molybdenum disulfide nanoscale enzyme, the coordination between the ionic groups of the polypeptide and the metal ions forms aggregates, inhibits the formation of agglomerates, and causes the polypeptide-assisted molybdenum disulfide nanoscale enzyme to have an amorphous phase structure with sulfur vacancies; And / or, the polypeptide-assisted molybdenum disulfide nanoscale enzyme is nanospherical, and the diameter is 500-600 nm.

9. The polypeptide-assisted molybdenum disulfide nanoscale enzyme in any one of claims 7-8 is used in a method for promoting algal growth or biomass conversion.

10. A method of promoting growth or biomass conversion of algae, characterized in that, The polypeptide-assisted molybdenum disulfide nanoscale enzyme is co-cultured with algae in a culture medium at a mass ratio of 1:500-1:10; And / or, the culture time is 0.5-7 days.

Images