Iron-carbon quantum dots / electroactive non-oxygenic photosynthetic bacteria / support hybrid cell factory and application thereof in sewage resourceization or carbon emission reduction

Abstract

The application belongs to the technical field of microbial sewage treatment, and particularly relates to an iron-carbon quantum dot / electrically active non-oxygen-producing photosynthetic bacteria / carrier hybrid cell factory and application thereof in sewage resourceization or carbon emission reduction; the iron-carbon quantum dot in the hybrid cell factory provided by the application promotes the non-oxygen-producing purple photosynthetic bacteria to utilize more light energy, and generates photo-generated electrons as an extracellular efficient electron donor source, and the photosensitive active substances in the extracellular polymeric substance of the non-oxygen-producing purple photosynthetic bacteria can promote the formation of a continuous cycle of trivalent iron and divalent iron, realize mutual cooperation, promote sewage resourceization and carbon emission reduction, and synthesize high-value-added products; and in addition to facilitating the recovery of biomass, the transparent conductive glass electrode as the carrier also ensures that the non-oxygen-producing purple photosynthetic bacteria stably and efficiently utilize light energy; therefore, the hybrid cell factory provided by the application is a high-efficiency microbial sewage treatment technology, and solves the technical problem of lack of high-efficiency microbial sewage treatment technology in the prior art.

Description

Technical Field

[0001] This application belongs to the field of microbial wastewater treatment technology, and in particular relates to iron-carbon quantum dot / electroactive non-aerobic photosynthetic bacteria / carrier hybrid cell factories and their applications in wastewater resource recovery or carbon emission reduction. Background Technology

[0002] Wastewater treatment is not only a process of water purification, but also an important part of achieving carbon neutrality. How to achieve low-carbon operation of wastewater treatment systems has become a major challenge for urban governance.

[0003] Low-carbon and high-value resource recovery of wastewater are two major new technological demands in wastewater treatment. Traditional activated sludge processes are energy inefficient and have insufficient resource recovery. Sludge landfilling or incineration further exacerbates the carbon footprint. Therefore, it is necessary to optimize processes or develop new low-carbon resource recovery technologies to overcome the low resource recovery rate and carbon emission problems in the wastewater treatment industry. Currently, the most commonly used technology for removing and recovering organic carbon from wastewater is anaerobic digestion to produce methanogens. However, this technology has significant drawbacks, such as the slow rate of microbial degradation of organic carbon leading to low methane yield; the reliance on the synergistic effect of multiple bacterial species (acid-producing, hydrogen-producing, and methanogenic bacteria) and the series connection of multiple process stages to achieve methanogenesis, resulting in complex process control; an unbalanced carbon-to-nitrogen ratio in wastewater (such as low carbon-to-nitrogen ratio wastewater) inhibits the activity of methanogenic bacteria, requiring additional adjustment of the carbon-to-nitrogen ratio; wastewater-derived methanogens are low-value-added products, and the biogas produced by anaerobic digestion has a low methane content (50%~70% methane). If purified into biogas (CH4>95%), the cost increases significantly.

[0004] Photosynthetic bacteria, as a special type of microorganism, are considered a promising next-generation wastewater resource recovery technology due to their unique metabolic patterns and pathways. Compared to other wastewater treatment microorganisms (ammonia-oxidizing bacteria, nitrite-oxidizing bacteria, denitrifying bacteria, polyphosphate-accumulating bacteria, etc.), photosynthetic bacteria can efficiently remove carbon, nitrogen, and phosphorus through direct uptake during wastewater treatment, using these to synthesize high-value resources such as carotenoids, chlorophyll, proteins, and 5-aminolevulinic acid, thus achieving the dual goals of efficient wastewater treatment and high-value resource recovery. Photosynthetic bacteria can be classified into aerobic, anaerobic, and facultative anaerobic bacteria. The aerobic metabolism of aerobic bacteria releases a large amount of carbon as carbon dioxide, resulting in high carbon emissions, while facultative anaerobic bacteria, under anaerobic light conditions, preferentially use carbon for biological processes. Biomass synthesis, reducing carbon emissions in the form of carbon dioxide, is a superior microbial wastewater treatment technology for achieving wastewater resource recovery and carbon reduction. However, in practical applications, the following problems still need to be solved regarding the biomass synthesis of high-value-added products from organic matter in wastewater by facultative anaerobic photosynthetic bacteria: Unlike the principle of photosynthetic autotrophic carbon fixation using inorganic carbon sources such as carbon dioxide, some carbon sources are still emitted as carbon dioxide during the synthesis of high-value-added products from organic matter by facultative anaerobic photosynthetic bacteria, resulting in relatively high carbon emissions. Furthermore, the efficiency and yield of facultative anaerobic photosynthetic bacteria in the targeted synthesis of high-value-added resources from wastewater organic matter are low, and the reuse of bacterial cells and biomass recovery are inconvenient. Therefore, it is necessary to develop a more efficient microbial wastewater treatment technology based on facultative anaerobic photosynthetic bacteria. Summary of the Invention

[0005] In view of this, this application provides an iron-carbon quantum dot / electroactive non-aerobic photosynthetic bacteria / carrier hybrid cell factory and its application in wastewater resource recovery or carbon emission reduction, in order to solve the technical problem of the lack of efficient microbial wastewater treatment technology in the prior art.

[0006] The first aspect of this application provides an iron-carbon quantum dot / electroactive non-oxygen-producing photosynthetic bacteria / carrier hybrid cell factory, including a transparent conductive glass electrode, electroactive non-oxygen-producing photosynthetic bacteria, and iron-carbon quantum dots;

[0007] The extracellular polymer secreted by the electroactive non-aerobic photosynthetic bacteria adsorbs the iron-carbon quantum dots to form a hybrid;

[0008] The hybrid is loaded onto the transparent conductive glass electrode.

[0009] Preferably, the transparent conductive glass electrode is selected from at least one of ITO transparent conductive glass electrode, FTO transparent conductive glass electrode, AZO transparent conductive glass electrode, and GZO transparent conductive glass electrode.

[0010] Preferably, the electroactive non-aerobic photosynthetic bacteria are selected from at least one of Rhodopseudomonas, Rhodospirillum, and Rhodophytes.

[0011] The second aspect of this application provides a method for preparing a hybrid cell factory of iron-carbon quantum dots / electroactive non-oxygen-producing photosynthetic bacteria / carrier, which can prepare the hybrid cell factory of iron-carbon quantum dots / electroactive non-oxygen-producing photosynthetic bacteria / carrier described in the first aspect, including the following steps:

[0012] The cultivation steps of purple non-sulfur non-oxygen photosynthetic bacteria: Under anaerobic light conditions, the purple non-sulfur non-oxygen photosynthetic bacteria from the bacterial culture center were inoculated and cultured in sequence to obtain purple non-sulfur non-oxygen photosynthetic bacteria solution.

[0013] The synthesis steps of iron-carbon quantum dots are as follows: water-soluble iron source and water-soluble carbon source are mixed and then subjected to hydrothermal reaction, centrifugation, and dialysis purification to obtain iron-carbon quantum dot solution;

[0014] Preparation steps of the hybrid cell factory: After placing the transparent conductive glass electrode into the electrochemical device reactor, a mixture including purple non-sulfur non-aerobic photosynthetic bacteria solution, iron-carbon quantum dot solution and culture medium is added, and voltage is applied to acclimate the cells under anaerobic light conditions. After acclimatization, an iron-carbon quantum dot / electroactive non-aerobic photosynthetic bacteria / carrier hybrid cell factory is obtained.

[0015] Preferably, in the cultivation step of the purple non-sulfur non-aerobic photosynthetic bacteria, the light wavelength is 380~780nm, the intensity is 10000~60000lx, and the temperature is 25~35℃.

[0016] Preferably, in the synthesis step of the iron-carbon quantum dots, the hydrothermal reaction temperature is 150~200℃ and the time is 5~15h; the centrifugal separation speed is 5000~15000 rpm·min. -1 The dialysis time is 10-30 minutes; the dialysis bags used for dialysis purification are 300-800 Da dialysis bags, and the dialysis time is 3-9 hours.

[0017] Preferably, in the synthesis step of the iron-carbon quantum dots, the water-soluble iron source used is selected from at least one of ferric nitrate, ferrous nitrate, ferric chloride, ferrous chloride, ferric sulfate, ferrous sulfate and their hydrates; the water-soluble carbon source used is selected from at least one of EDTA-2Na, sodium citrate, glucose and sucrose.

[0018] Preferably, in the preparation step of the hybrid cell factory, the volume ratio of the purple non-sulfur anaerobically aerobic photosynthetic bacteria solution, the iron-carbon quantum dot solution, and the culture medium in the mixture is 10~20:1~5:100; the concentration of the purple non-sulfur anaerobically aerobic photosynthetic bacteria solution is 1x10⁻⁶. 7 ~ 1x10 10 cell·L -1The concentration of the iron-carbon quantum dot solution is 100~300 mg / L.

[0019] Preferably, in the preparation step of the hybrid cell factory, the voltage applied during the acclimatization process is 0.1~0.4V, the light wavelength is 380~780nm, and the intensity is 10000~60000lx.

[0020] A third aspect of this application provides a wastewater resource recovery device, including an anaerobic baffle reactor and a power supply component;

[0021] The baffles in the anaerobic baffle reactor include the iron-carbon quantum dot / electroactive non-oxygen-producing photosynthetic bacteria / carrier hybrid cell factory described in the first aspect.

[0022] The power supply component is electrically connected to the baffle plate in the reaction chamber of the anaerobic baffle reactor.

[0023] Preferably, the anaerobic baffle reactor includes two reaction chambers connected in series;

[0024] Carbon rods are used as electrodes between baffles in two reaction chambers connected in series.

[0025] Preferably, the power supply component is a photovoltaic power supply component, a wind power supply component, a biomass power supply component, a hydropower power supply component, or a thermal power supply component.

[0026] The fourth aspect of this application provides an integrated wastewater resource recovery device, comprising at least two anaerobic baffle reactors as described in the third aspect, connected in series and / or in parallel.

[0027] Preferably, the anaerobic baffle reactor comprises 3 to 15 anaerobic baffle reactors.

[0028] The fifth aspect of this application provides the application of the iron-carbon quantum dot / electroactive non-oxygen-producing photosynthetic bacteria / carrier hybrid cell factory described in the first aspect in wastewater resource recovery or carbon emission reduction.

[0029] Compared with existing technologies, the iron-carbon quantum dot / electroactive non-aerobic photosynthetic bacteria / carrier hybrid cell factory provided in this application has at least the following beneficial effects:

[0030] 1. In the iron-carbon quantum dot / electroactive anaerobic photosynthetic bacteria / carrier hybrid cell factory provided in this application, iron-carbon quantum dots and anaerobic purple photosynthetic bacteria work synergistically. Iron-carbon quantum dots expand the spectral range of visible light for anaerobic purple photosynthetic bacteria to capture more light energy. Furthermore, the ferrous iron atoms and carbon quantum dots in the iron-carbon quantum dots can generate photogenerated electrons, which serve as an efficient extracellular electron donor source for carbon fixation by anaerobic purple photosynthetic bacteria. This promotes wastewater resource recovery and carbon emission reduction in the hybrid cell factory. Meanwhile, the photosensitive active substances in the extracellular polymers produced by anaerobic purple photosynthetic bacteria can promote the continuous cycling of ferric and ferrous iron, achieving synergy and thus promoting wastewater resource recovery and carbon emission reduction. It also enables the targeted synthesis of high-value-added products such as proteins, lycopene, and carotenoids, making it a highly efficient microbial wastewater treatment technology.

[0031] 2. In the iron-carbon quantum dot / electroactive anaerobic photosynthetic bacteria / carrier hybrid cell factory provided in this application, in addition to iron-carbon quantum dots and anaerobic purple photosynthetic bacteria, there is also a transparent conductive glass electrode. The transparent conductive glass electrode can serve as a carrier to load the iron-carbon quantum dot / electroactive anaerobic photosynthetic bacteria hybrid for easy biomass recovery. On the other hand, it can also ensure efficient light transmission, enabling the anaerobic purple photosynthetic bacteria to make efficient use of light energy and the stabilizing effect of the weak electric field on the anaerobic purple photosynthetic bacteria. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the specific embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0033] Figure 1 is a schematic diagram of the wastewater resource recovery device and the integrated wastewater resource recovery device provided in Embodiment 3 of this application; (a) Figure is a side view of the wastewater resource recovery device, (b) Figure is a top view of the wastewater resource recovery device, and (c) Figure is a side view and a top view of the integrated wastewater resource recovery device.

[0034] Figure 2 Electron micrograph and particle size diagram of iron-carbon quantum dots provided in Example 1 of this application;

[0035] Figure 3 This is a schematic diagram of the photoluminescence effect of iron-carbon quantum dots provided in Embodiment 1 of this application;

[0036] Figure 4 Transmission electron microscope schematic diagrams at different magnifications of the hybrid cell factory provided in Embodiment 2 of this application;

[0037] Figure 5This is a schematic diagram of the photoelectric response of the hybrid cell factory provided in Embodiment 2 and Comparative Example 1 of this application;

[0038] Figure 6 This is a schematic diagram illustrating the effect of the hybrid cell factory provided in Examples 1-2 and Comparative Example 1 of this application on the removal of sodium acetate;

[0039] Figure 7 This is a schematic diagram showing the RuBisCO enzyme and CO2 production in the hybrid cell factory provided in Examples 1-2 and Comparative Example 1 of this application;

[0040] Figure 8 This is a schematic diagram of the total protein, lycopene, and carotenoids synthesized by the hybrid cell factory provided in Examples 1-2 and Comparative Example 1 of this application;

[0041] The reference numerals in Figures 1(a) and 1(b) include: 1. Inlet pipe of anaerobic baffle reactor; 2. Baffle in first reaction chamber; 3. Baffle in second reaction chamber; 4. Pin in second reaction chamber; 5. Pin in first reaction chamber; 6. Voltage regulator of photovoltaic power supply component; 7. Carbon rod counter electrode; 8. First solar photovoltaic cell; 9. Second solar photovoltaic cell; 10. Inductive switch. Detailed Implementation

[0042] This application provides a hybrid cell factory of iron-carbon quantum dots / electroactive non-aerobic photosynthetic bacteria / carrier and its application in wastewater resource recovery or carbon emission reduction, in order to solve the technical problem of the lack of efficient microbial wastewater treatment technology in the prior art.

[0043] The technical solutions of this application will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0044] Example 1

[0045] This embodiment provides a method for preparing a hybrid cell factory of iron-carbon quantum dots / electroactive non-oxygen-producing photosynthetic bacteria / carrier, including a cultivation step of purple non-sulfur non-oxygen-producing photosynthetic bacteria, a synthesis step of iron-carbon quantum dots, and a preparation step of the hybrid cell factory.

[0046] The cultivation steps for purple non-sulfur anaerobically synthesizing bacteria include: Inoculating *Rhodopseudomonas* from the Guangdong Provincial Microbial Culture Collection Center onto a sterilized liquid culture medium (the culture medium preparation is shown in Table 1). Anaerobic culture at 30℃, 10000 lx light, and a wavelength of 580 nm for 6 days yields the seed culture of purple non-sulfur anaerobically synthesizing bacteria. Inoculating the cultured free bacteria using an inoculation loop, and then placing the culture in an incubator for further anaerobic light cultivation, followed by analysis using a hemocytometer, yielded a *Rhodopseudomonas* bacterial concentration of 1.75 x 10⁻⁶. 9 cell·L -1 .

[0047] The synthesis steps of iron-carbon quantum dots include: dissolving a mixture of 0.112 g of water-soluble carbon source EDTA-2Na and 0.202 g of water-soluble iron source Fe(NO3)3·9H2O in 30 mL of ultrapure water by stirring; then transferring the solution to a polytetrafluoroethylene-lined autoclave and heating it to 180 °C for 10 h; after cooling the reaction to room temperature, accelerating it at 10000 rpm·min. -1 Centrifuge at a speed of 20 min to remove large particles of product directly from the resulting solution; further purify the prepared product containing the solution by dialyzing in a 500 Da dialysis bag for 6 h (changing the water every 3 h) to obtain an iron-carbon quantum dot (Fe-CQDs) solution with a concentration of approximately 200 mg / L, and store it at 4 °C for later use.

[0048] The preparation steps of a hybrid cell factory include:

[0049] Weigh Rhodopseudomonas aeruginosa bacterial suspension, Fe-CQDs solution, and liquid culture medium according to a volume ratio of 15:1.5:100. Place a plate-shaped ITO transparent conductive glass electrode into the electrochemical device reactor beforehand. Then, inoculate the Rhodopseudomonas aeruginosa bacterial suspension into the liquid culture medium, add Fe-CQDs solution to the inoculated liquid culture medium to obtain a mixture, place the mixture in the electrochemical device reactor, and seal the anaerobic electrochemical reactor with a butyl rubber stopper and a porous aluminum cap to establish and maintain an anaerobic environment.

[0050] Anaerobic culture was carried out under 10000 lx light and 580 nm wavelength light, and a positive voltage of 0.2 V was applied to the ITO transparent conductive glass electrode for batch culture. The nutrient solution was changed every 7 days. In each cycle, the bacterial growth density (OD600 value), the conversion rate of organic carbon in the culture medium, the secondary utilization rate of CO2, the composition and content of extracellular polymers, and the accumulation of resource products were monitored. When the fluctuation range of all monitored parameters was less than ±10% in three consecutive cycles, the bacterial domestication was determined to be complete, and a hybrid cell factory of iron-carbon quantum dots / electroactive non-aerobic photosynthetic bacteria / carrier was obtained. In the hybrid cell factory of iron-carbon quantum dots / electroactive non-aerobic photosynthetic bacteria / carrier, the extracellular polymers secreted by Rhodopseudomonas adsorbed iron-carbon quantum dots to form hybrid bodies and were attached to the ITO transparent conductive glass electrode.

[0051] Example 2

[0052] This embodiment provides a method for preparing a hybrid cell factory of iron-carbon quantum dots / electroactive non-oxygen-producing photosynthetic bacteria / carrier, including a cultivation step of purple non-sulfur non-oxygen-producing photosynthetic bacteria, a synthesis step of iron-carbon quantum dots, and a preparation step of the hybrid cell factory.

[0053] The cultivation steps for purple non-sulfur anaerobically synthesizing bacteria include: Inoculating *Rhodopseudomonas* from the Guangdong Provincial Microbial Culture Collection Center onto a sterilized liquid culture medium (the culture medium preparation is shown in Table 1). Anaerobic culture at 30℃, 10000 lx light, and a wavelength of 580 nm for 6 days yields the seed culture of purple non-sulfur anaerobically synthesizing bacteria. Inoculating the cultured free bacteria using an inoculation loop, and then placing the culture in an incubator for further anaerobic light cultivation, followed by analysis using a hemocytometer, yielded a *Rhodopseudomonas* bacterial concentration of 1.75 x 10⁻⁶. 9 cell·L -1 .

[0054] The synthesis steps of iron-carbon quantum dots include: dissolving a mixture of 0.112 g of water-soluble carbon source EDTA-2Na and 0.202 g of water-soluble iron source Fe(NO3)3·9H2O in 30 mL of ultrapure water by stirring; then transferring the solution to a polytetrafluoroethylene-lined autoclave and heating it to 180 °C for 10 h; after cooling the reaction to room temperature, accelerating it at 10000 rpm·min. -1 Centrifuge at a speed of 20 min to remove large particles of product directly from the resulting solution; further purify the prepared product containing the solution by dialyzing in a 500 Da dialysis bag for 6 h (changing the water every 3 h) to obtain an iron-carbon quantum dot (Fe-CQDs) solution with a concentration of approximately 200 mg / L, and store it at 4 °C for later use.

[0055] The preparation steps of a hybrid cell factory include:

[0056] According to a volume ratio of 15:3:100, Rhodopseudomonas erythrosporum bacterial suspension, Fe-CQDs solution, and liquid culture medium were weighed, and a plate-shaped ITO transparent conductive glass electrode was pre-placed in the electrochemical device reactor. Then, the Rhodopseudomonas erythrosporum bacterial suspension was inoculated into the liquid culture medium, and Fe-CQDs solution was added to the inoculated liquid culture medium to obtain a mixture. The mixture was placed in the electrochemical device reactor, and the anaerobic electrochemical reactor was sealed with a butyl rubber stopper and a porous aluminum cap to establish and maintain an anaerobic environment.

[0057] Anaerobic culture was carried out under 10000 lx light and 580 nm wavelength light, and a positive voltage of 0.2 V was applied to the ITO transparent conductive glass electrode for batch culture. The nutrient solution was changed every 7 days. In each cycle, the bacterial growth density (OD600 value), the conversion rate of organic carbon in the culture medium, the secondary utilization rate of CO2, the composition and content of extracellular polymers, and the accumulation of resource products were monitored. When the fluctuation range of all monitored parameters was less than ±10% in three consecutive cycles, the bacterial domestication was determined to be complete, and a hybrid cell factory of iron-carbon quantum dots / electroactive non-aerobic photosynthetic bacteria / carrier was obtained. In the hybrid cell factory of iron-carbon quantum dots / electroactive non-aerobic photosynthetic bacteria / carrier, the extracellular polymers secreted by Rhodopseudomonas adsorbed iron-carbon quantum dots to form hybrid bodies and were attached to the ITO transparent conductive glass electrode.

[0058] Example 3

[0059] This embodiment provides a wastewater resource recovery device based on the iron-carbon quantum dot / electroactive non-aerobic photosynthetic bacteria / carrier hybrid cell factory provided in Embodiment 1. Schematic diagrams of the wastewater resource recovery device are shown in Figures (a) and (b) of Figure 1.

[0060] The wastewater resource recovery device provided in this embodiment includes an anaerobic baffle reactor. An inlet pipe 1 is located at the bottom of the anaerobic baffle reactor, allowing organic wastewater to flow into and towards the reaction chamber during operation. The anaerobic baffle reactor contains two reaction chambers connected in series: a first reaction chamber and a second reaction chamber. The first and second reaction chambers are respectively equipped with baffles 2 and 3. Baffles 2 and 3 include multiple flat-plate-shaped iron-carbon quantum dot / electroactive non-aerobic photosynthetic bacteria / carrier hybrid cell factories provided in Embodiment 1, and are fixed by pins 4 and 5 connected with wires, ensuring high light transmittance, flexible blade adjustment, greater bacterial load, and convenient biomass harvesting. Carbon rods are arranged between the two baffles 2 and 3. Electrode 7; In addition, a photovoltaic power generation component is connected to the outside of the anaerobic baffle reactor. The photovoltaic power generation component is electrically connected to baffle 2 and baffle 3 through wires. The photovoltaic power generation component includes a first solar photovoltaic cell 8 and a second solar photovoltaic cell 9 connected in parallel, an induction switch 10, and a voltage regulator 6. During the day, the induction switch 10 is opened, and the first solar photovoltaic cell 8 supplies power to the circuit, forming a weak electric field between baffle 2, baffle 3, and the carbon rod opposite electrode 7. At the same time, the second solar photovoltaic cell 9 stores electrical energy. At night, the induction switch 10 is closed, and the second solar photovoltaic cell 9, which stores electrical energy during the day, supplies power to the circuit, thereby achieving continuous power supply throughout the day to maintain the weak electric field. The voltage regulator 6 can provide a stable circuit current for the circuit.

[0061] Example 4

[0062] This embodiment provides an integrated wastewater resource recovery device based on the wastewater resource recovery device provided in Embodiment 3. The schematic diagram of the integrated wastewater resource recovery device is shown in Figure 1(c).

[0063] The integrated wastewater resource recovery device provided in this embodiment includes nine wastewater resource recovery devices, namely units 1 to 9. Units 1 to 3 are connected in series, units 4 to 6 are connected in series, and units 7 to 9 are connected in series. Units 1 to 3, units 4 to 6, and units 7 to 9 are connected in parallel.

[0064] Comparative Example 1

[0065] This comparative example provides a method for preparing an electroactive non-oxygen-producing photosynthetic bacteria / carrier hybrid cell factory. It includes the culturing steps of purple non-sulfur non-oxygen-producing photosynthetic bacteria and the preparation steps of the hybrid cell factory.

[0066] The cultivation steps for purple non-sulfur anaerobically synthesizing bacteria include: Inoculating *Rhodopseudomonas* from the Guangdong Provincial Microbial Culture Collection Center onto a sterilized liquid culture medium (the culture medium preparation is shown in Table 1). Anaerobic culture at 30℃, 10000 lx light, and a wavelength of 580 nm for 6 days yields the seed culture of purple non-sulfur anaerobically synthesizing bacteria. Inoculating the cultured free bacteria using an inoculation loop, and then placing the culture in an incubator for further anaerobic light cultivation, followed by analysis using a hemocytometer, yielded a *Rhodopseudomonas* bacterial concentration of 1.75 x 10⁻⁶. 9 cell·L -1 .

[0067] The preparation steps of a hybrid cell factory include:

[0068] Weigh Rhodopseudomonas erythrosporum bacterial suspension and liquid culture medium at a volume ratio of 15:100, and pre-place a plate-shaped ITO transparent conductive glass electrode into the electrochemical device reactor; then inoculate the Rhodopseudomonas erythrosporum bacterial suspension into the liquid culture medium to obtain a mixture, place the mixture in the electrochemical device reactor, and seal the anaerobic electrochemical reactor with a butyl rubber stopper and a porous aluminum cap to establish and maintain an anaerobic environment;

[0069] Anaerobic culture was carried out under 10000 lx light and 580 nm wavelength light, and a positive voltage of 0.2 V was applied to the ITO transparent conductive glass electrode for batch culture. The nutrient solution was changed every 7 days. In each cycle, the bacterial growth density (OD600 value), the conversion rate of organic carbon in the culture medium, the secondary utilization rate of CO2, the composition and content of extracellular polymers, and the accumulation of resource products were monitored. When the fluctuation range of all monitored parameters was less than ±10% in three consecutive cycles, the bacterial domestication was deemed to be completed, and an electroactive non-aerobic photosynthetic bacteria / carrier hybrid cell factory was obtained. The extracellular polymers secreted by Rhodopseudomonas aeruginosa in the electroactive non-aerobic photosynthetic bacteria / carrier hybrid cell factory adhered and loaded onto the ITO transparent conductive glass electrode.

[0070] Experimental Example 1

[0071] This experimental example characterizes the structure and properties of the iron-carbon quantum dots and hybrid cell factories provided in Examples 1-2 and Comparative Example 1.

[0072] Among them, the electron micrograph and particle size of the iron-carbon quantum dots provided in Example 1 are as follows: Figure 2 As shown, the photoluminescence effect is characterized as follows: Figure 3 As shown; from Figure 2It can be seen that the size of iron-carbon quantum dots is mainly distributed in the range of 1.0~2.0 nm, and the average particle size obtained from the normal distribution curve is 1.7 nm, which is a typical size for quantum dots. High-resolution electron microscopy images show that iron-carbon quantum dots have obvious lattice fringes, which coincide with the (100) crystal plane of graphene, indicating that they possess graphene-like crystal structure characteristics. Figure 3 As shown in the photoluminescence effect diagram, under simulated sunlight irradiation, its photocurrent density rapidly increases to 12.5 ± 0.8 μA within 0.5 seconds. After the light source is turned off, the current decays to less than 90% of the irradiation value within 1.2 seconds, indicating that it has rapid charge separation and transport dynamics. This response behavior is highly repeatable and maintains a stable photoresponse, confirming the broad-spectrum trapping ability and photocorrosion resistance of the iron-carbon quantum dots. This provides a material basis for expanding the spectral range of visible light utilized by non-aerobic purple photosynthetic bacteria and improving the electron transfer efficiency of photoelectric synergistic microbial systems.

[0073] Transmission electron microscope images of the hybrid cell factory provided in Example 2 at different magnifications are shown below. Figure 4 As shown, the photoelectric response characterization of the hybrid cell factory provided in Example 2 and Comparative Example 1 is as follows. Figure 5 As shown; from Figure 4 It can be observed that purple non-sulfur aerobic photosynthetic bacteria aggregate through conductive bands, indicating that iron-carbon quantum dots can promote the transfer of extracellular electrons in bacteria; and from Figure 5 It can be seen that the highest photocurrent response of the hybrid cell factory provided in Comparative Example 1 is only 0.21 μA, while the photoresponse intensity of the hybrid cell factory provided in Example 2 is 0.87 μA. This indicates that because iron-carbon quantum dots are adsorbed in the extracellular polymer in the hybrid cell factory provided in Example 2, the spectral range of visible light is expanded by taking advantage of the broad-spectrum capture capability and anti-photocorrosion properties of iron-carbon quantum dots, more light energy is captured, and the energy / electron transfer to the bacterial photosynthetic system is enhanced, thereby increasing the production of photogenerated electrons and participating in the extracellular electron transfer (EET) process.

[0074] Experimental Example 2

[0075] This experiment investigated the wastewater resource recovery and carbon emission reduction of the hybrid cell factories provided in Examples 1-2 and Comparative Example 1. The experimental process involved first preparing the wastewater nutrient solution according to Table 1, and then placing the hybrid cell factories provided in Examples 1-2 and Comparative Example 1 in the simulated wastewater nutrient solution under anaerobic conditions with 10,000 lx light to explore the effects of the hybrid cell factories on wastewater resource recovery, generation of high-value-added products, carbon sequestration, and carbon emission reduction.

[0076] The carbon fixation effect experiment lasted for 144 hours, with sampling times of 0, 24, 48, 72, 96, 120, and 144 hours. Three parallel groups were used to reduce experimental error. High-performance liquid chromatography (HPLC, Essentia LC-16; Shimadzu Corporation, Japan) was used to determine the sodium acetate (carbon acetate) content in the system. The mobile phase consisted of phosphoric acid solution at pH 2.15 and ultrapure water. A C18 column (0.46 × 15 cm; 5 μm, Phenomenex, CA, USA) was used for separation. The temperature was set at 35℃, the flow rate at 1 mL / min, and the wavelength at 210 nm. Microbial gas production was collected using a microsyringe, and the CO2 content was determined by gas chromatography (GC) equipped with a thermal conductivity detector (TCD). The results of the carbon fixation effect experiment are shown in Table 2 and... Figure 6 , Figure 7 As shown in Figure (a) in Table 2, the removal rate of sodium acetate (carbon acetate) is obtained by formula C0-C t Calculated by / C0*100%, C0 and C t These represent the initial concentration of sodium acetate (carbon acetate) and the concentration after a certain period of carbon fixation, respectively.

[0077] The experiment on wastewater resource recovery to generate high-value-added products lasted 120 hours and was conducted in triplicate to minimize experimental error. The experiment used a kit to determine the content of RuBisCo enzyme, total bacterial protein, and carotenoids in the high-value-added products, while lycopene was determined spectrophotometrically. The results of the wastewater resource recovery to high-value-added products experiment are shown in Table 3. Figure 8 As shown.

[0078] From Table 2 and Figure 6 , Figure 7 As shown in Figure (a), the carbon fixation and carbon emission reduction effects of different hybrid cell factories vary. The hybrid cell factory provided in Comparative Example 1 has a slower efficiency in removing sodium acetate (acetic acid carbon) and produces more carbon dioxide. For example, after 144 hours, the hybrid cell factory provided in Comparative Example 1 has a removal rate of 86% for sodium acetate (acetic acid carbon) and a carbon dioxide production of 2.23 mmol / L, while the hybrid cell factories provided in Examples 1 and 2 have removal rates of 88.7% and 89.3% for sodium acetate (acetic acid carbon), respectively, and carbon dioxide production is around 2.05 mmol / L. This indicates that the hybrid cell factories provided in Examples 1-2 can promote the directional conversion of organic carbon sodium acetate (acetic acid carbon) into biological carbon fixation products. Under photosynthetic heterotrophic conditions, the oxidative degradation process of sodium acetate (acetic acid carbon) forms a synergistic effect with photosynthesis, driving the improvement of secondary CO2 fixation efficiency. The CO2 produced by degradation is assimilated in situ by microorganisms through the Calvin cycle, ultimately realizing the resource utilization of total carbon in wastewater and reducing carbon emissions.

[0079] From Table 3 and Figure 7 Figure (b) in the middle and Figure 8 It can be seen that different hybrid cell factories have different effects on the resource recovery of wastewater and the generation of high-value-added products. The hybrid cell factory provided in Comparative Example 1 has lower RuBisCO enzyme activity and a smaller amount of high-value-added products generated. RuBisCO enzyme is a key enzyme in the CBB cycle and can catalyze CO2 fixation. The hybrid cell factories provided in Examples 1 and 2 have higher RuBisCO enzyme activity, which can promote CO2 fixation and convert it into high-value-added products such as total bacterial protein, carotene, and lycopene, thus realizing the resource recovery of wastewater and the generation of high-value-added products.

[0080] Through wastewater resource utilization and carbon emission reduction experiments, it can be demonstrated that because iron-carbon quantum dots are adsorbed in the extracellular polymers of the hybrid cell factory provided in Examples 1-2, the photogenerated electrons generated by the iron-carbon quantum dots can simultaneously serve as an efficient extracellular electron donor source for carbon fixation by non-oxygen-producing purple photosynthetic bacteria. Furthermore, the photosensitive active substances in the extracellular polymers, or through a weak electric field, also promote the continuous cycling of trivalent / divalent iron, achieving mutual synergy. Thus, organic carbon such as sodium acetate (acetic acid carbon) and emitted inorganic carbon are fully utilized by purple non-sulfur non-oxygen-producing photosynthetic bacteria to directionally synthesize high-value-added products such as proteins, lycopene, and carotenoids.

[0081] Table 1

[0082]

[0083] Table 2

[0084]

[0085] Table 3

[0086]

[0087] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A hybrid cell factory consisting of iron-carbon quantum dots / electroactive non-aerobic photosynthetic bacteria / carrier, characterized in that, Including transparent conductive glass electrodes, electroactive non-aerobic photosynthetic bacteria, and iron-carbon quantum dots; The extracellular polymer secreted by the electroactive non-aerobic photosynthetic bacteria adsorbs the iron-carbon quantum dots to form a hybrid; The hybrid is supported on the transparent conductive glass electrode; The preparation method of the iron-carbon quantum dot / electroactive non-aerobic photosynthetic bacteria / carrier hybrid cell factory includes the following steps: The cultivation steps of purple non-sulfur non-oxygen photosynthetic bacteria: Under anaerobic light conditions, the purple non-sulfur non-oxygen photosynthetic bacteria from the bacterial culture center were inoculated and cultured in sequence to obtain purple non-sulfur non-oxygen photosynthetic bacteria solution. The synthesis steps of iron-carbon quantum dots are as follows: water-soluble iron source and water-soluble carbon source are mixed and then subjected to hydrothermal reaction, centrifugation, and dialysis purification to obtain iron-carbon quantum dot solution. The hydrothermal reaction temperature is 150~200℃ and the time is 5~15h. Preparation steps of the hybrid cell factory: After placing the transparent conductive glass electrode into the electrochemical device reactor, add a mixture of purple non-sulfur non-aerobic photosynthetic bacteria solution, iron-carbon quantum dot solution and culture medium, and apply voltage to acclimate under anaerobic light conditions. After acclimatization, the iron-carbon quantum dot / electroactive non-aerobic photosynthetic bacteria / carrier hybrid cell factory is obtained. The water-soluble iron source is selected from at least one of ferric nitrate, ferrous nitrate, ferric chloride, ferrous chloride, ferrous sulfate, ferrous sulfate and their hydrates; The water-soluble carbon source is selected from at least one of EDTA-2Na, sodium citrate, glucose, and sucrose.

2. The iron-carbon quantum dot / electroactive non-aerobic photosynthetic bacteria / carrier hybrid cell factory according to claim 1, characterized in that, The transparent conductive glass electrode is selected from at least one of ITO transparent conductive glass electrode, FTO transparent conductive glass electrode, AZO transparent conductive glass electrode, and GZO transparent conductive glass electrode.

3. The iron-carbon quantum dot / electroactive non-aerobic photosynthetic bacteria / carrier hybrid cell factory according to claim 1, characterized in that, The electroactive non-aerobic photosynthetic bacteria are selected from at least one of Rhodopseudomonas, Rhodospirillum, and Rhodophytes.

4. The iron-carbon quantum dot / electroactive non-aerobic photosynthetic bacteria / carrier hybrid cell factory according to claim 1, characterized in that, In the preparation steps of the hybrid cell factory, the volume ratio of the purple non-sulfur anaerobically aerobic photosynthetic bacteria solution, iron-carbon quantum dot solution, and culture medium in the mixture is 10~20:1~5:100; the concentration of the purple non-sulfur anaerobically aerobic photosynthetic bacteria solution is 1x10⁻⁶. 7 ~1x10 10 cell·L -1 The concentration of the iron-carbon quantum dot solution is 100~300 mg / L.

5. A hybrid cell factory of iron-carbon quantum dots / electroactive non-aerobic photosynthetic bacteria / carrier according to claim 1, characterized in that, In the preparation steps of the hybrid cell factory, the voltage applied during the domestication process is 0.1~0.4V, the light wavelength is 380~780nm, and the intensity is 10000~60000lx.

6. A wastewater resource recovery device, characterized in that, It includes an anaerobic baffled reactor and a power supply component; the baffles in the anaerobic baffled reactor include the iron-carbon quantum dot / electroactive non-aerobic photosynthetic bacteria / carrier hybrid cell factory as described in any one of claims 1-5; The power supply component is electrically connected to the baffle plate in the reaction chamber of the anaerobic baffle reactor.

7. An integrated wastewater resource recovery device, characterized in that, Includes at least two series and / or parallel The anaerobic baffled reactor according to claim 6 of the United States.

8. The application of the iron-carbon quantum dot / electroactive non-aerobic photosynthetic bacteria / carrier hybrid cell factory according to any one of claims 1-5 in wastewater resource recovery or carbon emission reduction.

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