System and method for electro-enhanced white rot fungi to degrade emerging contaminants in water

Abstract

This invention discloses a system and method for electro-enhanced white-rot fungi degradation of new pollutants in water, belonging to the field of water pollution control and ecological restoration technology. The system includes an electric field control unit and an immobilized white-rot fungi reaction zone. The electric field control unit includes several anode and cathode plates connected to a DC power supply, inserted parallel to each other in the reactor. Between adjacent anode and cathode plates, a conductive composite carrier with attached white-rot fungi is filled to form an immobilized white-rot fungi layer. This invention utilizes an electric field-enhanced immobilized white-rot fungi system. After applying a weak electric field, under appropriate voltage gradient, plate spacing, and energizing mode, the secretory activity of the lignin-degrading enzyme system of the white-rot fungi is significantly activated, thereby greatly improving the degradation efficiency and mineralization degree of new pollutants such as antibiotics and endocrine disruptors in water.

Description

Technical Field

[0001] This invention relates to the field of water environment pollution control and ecological restoration technology, specifically to a system and method for efficiently degrading new pollutants in water by utilizing a weak electric field enhancement, a conductive composite carrier, and the synergistic effect of white-rot fungi. Background Technology

[0002] In recent years, "new pollutants," represented by antibiotics, endocrine disruptors, microplastics, and personal care products, have been frequently detected in the aquatic environment. These pollutants are characterized by complex structures, high biotoxicity, and easy bioaccumulation, making them difficult to effectively remove using traditional water treatment processes (such as conventional biological methods and flocculation sedimentation). White-rot fungi, due to their ability to secrete non-specific extracellular lignin-degrading enzyme systems (including lignin peroxidase, manganese peroxidase, and laccase), have shown great potential in degrading various recalcitrant organic compounds.

[0003] However, directly applying free white-rot fungi to practical water treatment projects faces several technical bottlenecks: First, free fungi are easily inhibited by competition from native bacteria in non-sterilized open environments, leading to biomass loss and decreased enzyme activity; second, the enzyme production cycle of fungi in conventional water environments is long, and the enzyme secretion is unstable, making it difficult to meet the degradation rate requirements of continuous flow treatment. Although immobilization technology has alleviated the problem of cell loss to some extent, simple physical adsorption by the carrier has failed to fundamentally stimulate the metabolic potential of fungi.

[0004] Weak electric field stimulation, as a novel environmental regulation method, has been shown to increase the permeability of microbial cell membranes, promoting transmembrane transport of substrates and the secretion of secondary metabolites. If weak electric field technology can be coupled with immobilized white-rot fungi systems, and enzyme production by fungi can be enhanced through the targeted application of electric fields, it is expected to overcome the efficiency bottleneck of existing fungal treatment processes.

[0005] However, current technologies lack a systematic design targeting the deep microecological synergy mechanism among weak electric fields, conductive carriers, and white-rot fungi. Inappropriate electric field configurations not only fail to effectively stimulate enzyme activity but may also lead to excessive accumulation of reactive oxygen species, resulting in cytotoxicity and inhibiting fungal growth.

[0006] Based on this, the present invention aims to develop a system and method for the efficient degradation of new pollutants in water by electrically enhanced white-rot fungi coupled with conductive composite carriers. Summary of the Invention

[0007] The purpose of this invention is to address the problems of existing white-rot fungal systems for degrading new pollutants, such as susceptibility to inhibition by other microorganisms, low enzyme production efficiency, and slow degradation rate, by providing an electrically enhanced system and method for the degradation of new pollutants in water by white-rot fungi. This invention utilizes an electric field to enhance the immobilized white-rot fungal system. After applying a weak electric field, under appropriate voltage gradient, electrode spacing, and energizing mode, the secretory activity of the lignin-degrading enzyme system of the white-rot fungi is significantly activated, thereby greatly improving the degradation efficiency and mineralization degree of new pollutants such as antibiotics and endocrine disruptors in water.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A system for electrically enhanced degradation of new pollutants in water by white-rot fungi includes an electric field control unit and a reaction zone for immobilized white-rot fungi; wherein, The electric field control unit includes several sets of anode plates and cathode plates connected to a DC regulated power supply, which are inserted into the reactor water. Between the adjacent anode and cathode plates, a conductive composite carrier is filled, and white-rot fungi are attached and grown on the conductive composite carrier to form an immobilized white-rot fungal layer.

[0009] Furthermore, the anode plate and cathode plate are graphite electrode plates, which have good biocompatibility and conductivity, and are inexpensive.

[0010] Furthermore, the distance between adjacent anode plates and cathode plates is 5-8 cm, preferably 6 cm.

[0011] Furthermore, the conductive composite carrier is pyrite-modified carbon felt, wherein the mass percentage of pyrite is 10%-15%.

[0012] Furthermore, the filling rate of the conductive composite carrier between adjacent anode plates and cathode plates is 30-60%, preferably 50%.

[0013] Furthermore, the white-rot fungi include, but are not limited to: *Procambarus chrysospora* (…). Phanerochaete chrysosporium ), colorful Trametes ( Trametes versicolor ) or rough-skinned side ear ( Pleurotus ostreatus ), preferably *Procambarus chrysosporus* ( Phanerochaete chrysosporium This strain is highly adaptable to the environment and can secrete large amounts of lignin peroxidase, manganese peroxidase, and laccase under suitable stress.

[0014] A method for electro-enhanced degradation of new pollutants in water by white-rot fungi, the specific steps of which are as follows: System configuration: Anode plates and cathode plates are inserted in parallel within the main reaction zone of the reactor; Carrier and microbial community configuration: The cultured white-rot fungi were inoculated onto a conductive composite carrier for immobilization culture until the hyphae fully wrapped and penetrated the carrier pores. Then, the fungi were filled between adjacent anode and cathode plates to form an immobilized white-rot fungal layer. Electric field coupling operation: Connect wastewater containing new pollutants, turn on the DC regulated power supply, and set the operating parameters of the electric field control unit.

[0015] Furthermore, the wastewater containing the new pollutants includes one or more of tetracycline, bisphenol A, ciprofloxacin, and estradiol.

[0016] Furthermore, a microporous titanium alloy aeration disc is laid at the bottom of the reactor to provide sufficient dissolved oxygen to the water body at a constant aeration rate of 0.2~1 L / min.

[0017] Furthermore, the operating parameters of the electric field control unit are set as follows: voltage 1.5 V, power-on time 12 h per day, and plate spacing 5~8 cm.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention achieves efficient and rapid degradation of typical novel pollutants (such as tetracycline and bisphenol A) by constructing a three-dimensional coupling system of "micro-electric field-conductive composite carrier-white-rot fungus". The system applies an optimized micro-electric field (optimal parameters are 1.5 V voltage and 6 cm electrode spacing) as a mild environmental stress signal, which targets and activates the secondary metabolic pathways of white-rot fungi, resulting in a 2-3 fold increase in the expression and secretion activity of extracellular lignin-degrading enzymes (especially laccase and manganese peroxidase) compared to the natural state. Under synergistic effects, the system can stably maintain a removal rate of over 75% for the target novel pollutant (tetracycline).

[0019] 2. This invention reshapes the mass transfer process between fungi and pollutants at the level of microecological regulation. Pyrite-modified carbon felt, as a conductive carrier, not only provides a sanctuary for white-rot fungi free from the shear force of water flow, but its excellent conductivity also eliminates conductive blind spots within the immobilized bed. Attached Figure Description

[0020] Figure 1 The images are TEM images of white-rot fungi after being powered on, with (ac) magnifications of 15,000×, 60,000× and 150,000×, respectively. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments and comparative examples. Example

[0022] The specific steps for building and running this system are as follows: 1. Construction of the reactor and electric field control unit This embodiment involves inserting graphite anode and cathode plates in parallel within a rectangular reactor with an effective volume of 2 L (preferably arranged in an ABABAB configuration to effectively utilize both plates), with a plate spacing of 6 cm. Specifically, the reactor body is made of high-transmittance PMMA (polymethyl methacrylate) material, with internal dimensions of 15 cm long, 10 cm wide, and 20 cm high. The selected graphite electrode plates are 10 cm × 15 cm in size and 3 mm thick, exhibiting excellent conductivity and biocompatibility. An external thermostatic water bath jacket is fitted to the reactor to maintain a constant reaction system temperature of 28 ± 1 °C. A microporous titanium alloy aeration disc is laid at the bottom of the reactor to provide sufficient dissolved oxygen to the water at a constant aeration rate of 0.5 L / min to meet the aerobic metabolic needs of the fungi.

[0023] 2. Carrier modification and preparation of immobilized fungi Phanerochaete chrysosporium (purchased from Wuhan Huanna Biotechnology Co., Ltd.) was inoculated into a 6 cm × 10 cm × 2 cm substrate containing 15% pyrite-modified carbon felt and cultured in a shaker at 28°C for 5 days until the hyphae completely covered the surface of the substrate and penetrated the internal pores, forming an immobilized white-rot fungal complex.

[0024] The preparation steps of pyrite-modified carbon felt are as follows: First, the carbon felt skeleton is pretreated by ultrasonic cleaning and dilute acid soaking in sequence to remove impurities and ash from its surface. Subsequently, pyrite was grown in situ and loaded into the internal network of carbon felt using a hydrothermal synthesis method. The specific process was as follows: the pretreated carbon felt was immersed in a prepared hydrothermal precursor solution containing iron and sulfur sources, and then transferred to a closed reactor lined with polytetrafluoroethylene, and reacted at 180°C for 18 hours. After the reaction is complete, FeS2 can be loaded onto the carbon felt skeleton and pore surface by thorough washing and vacuum drying.

[0025] During the inoculation phase, the prepared concentration was 1.0 × 10⁻⁶. 6 Phanerochaete chrysospora ( cells / mL) Phanerochaete chrysosporium Spore suspension was added to Kirk liquid medium at an inoculum of 10% (v / v), and then pyrite-modified carbon felt was placed in the medium to allow Protozoa chrysospora to attach to its surface and form a biofilm.

[0026] The obtained immobilized white-rot fungal complex was uniformly packed between two adjacent electrode plates at a loading rate of 50%, thereby forming a porous, high specific surface area immobilized white-rot fungal reaction layer in the reactor.

[0027] 3. Setting of electric field coupling operating parameters Simulated new pollutant wastewater was introduced, with tetracycline, a typical antibiotic, as the target pollutant. The initial influent concentration was 20 mg / L, and the pH was adjusted to 5.5. To ensure suitable conductivity and maintain a stable micro-electric field, 0.05 mol / L anhydrous sodium sulfate was added to the influent as a supporting electrolyte. The system was put into continuous flow operation mode, with the influent flow rate controlled by a high-precision peristaltic pump, and the hydraulic retention time (HRT) controlled at 12 h. Subsequently, a DC regulated power supply was turned on, and the electric field operating parameters were controlled as follows: a constant voltage of 1.5 V, continuously energized. This small voltage can form an effective potential gradient while avoiding water electrolysis side reactions caused by excessive voltage.

[0028] 4. Effect Verification and In-Depth Mechanism Analysis After the system ran continuously for 2 days (12 hours of continuous power supply per day), the removal rate of tetracycline reached as high as 80%.

[0029] Measurements of lignin-degrading enzyme systems in water showed that an electric field targeted and activated enzyme expression, with the activities of manganese peroxidase and laccase in the system increasing by two times compared to the natural state. Figure 1 As shown, the hyphae on the surface of the conductive carrier are full, proving that the 1.5 V voltage gradient provides effective electrical stimulation without causing irreversible damage to the fungal cell membrane. Comparative Example 1

[0030] This comparative example has the same system and carrier configuration as Example 1, but the DC regulated power supply is not turned on (i.e., it is in a state of natural immobilized fungal degradation).

[0031] Performance verification: Within the same running time (48 h), the removal rate of tetracycline was only 52.3%. Enzyme activity within the system remained at a low baseline level, and as the reaction proceeded, the degradation rate showed a significant decreasing trend due to limited substrate mass transfer and product inhibition. This confirms the irreplaceable role of introducing a 1.5 V micro-electric field in Example 1 in breaking through the mass transfer bottleneck and stimulating efficient enzyme production by white-rot fungi.

[0032] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A system for electro-enhanced white-rot fungi to degrade new pollutants in water, characterized in that, The system includes an electric field control unit and a reaction zone for immobilized white-rot fungi; wherein, The electric field control unit includes several sets of anode plates and cathode plates connected to a DC regulated power supply, which are inserted into the reactor water. Between the adjacent anode and cathode plates, a conductive composite carrier is filled, and white-rot fungi are attached and grown on the conductive composite carrier to form an immobilized white-rot fungal layer.

2. The system according to claim 1, characterized in that, The anode plate and cathode plate are graphite electrode plates.

3. The system according to claim 1, characterized in that, The distance between adjacent anode plates and cathode plates is 5-8 cm.

4. The system according to claim 1, characterized in that, The conductive composite carrier is pyrite-modified carbon felt, wherein the mass percentage of pyrite is 10%-15%.

5. The system according to claim 1, characterized in that, The filling rate of the conductive composite carrier between adjacent anode and cathode plates is 30-60%.

6. The system according to claim 1, characterized in that, The white-rot fungi include, but are not limited to: *Phanerochaete chrysosporium* (… Phanerochaete chrysosporium ), colorful Trametes ( Trametes versicolor ) or rough-skinned side ear ( Pleurotus ostreatus ).

7. A method for electro-enhanced degradation of new pollutants in water by white-rot fungi, characterized in that, The specific steps of this method are as follows: System configuration: Anode plates and cathode plates are inserted in parallel within the main reaction zone of the reactor; Carrier and microbial community configuration: The cultured white-rot fungi were inoculated onto a conductive composite carrier for immobilization culture until the hyphae fully wrapped and penetrated the carrier pores. Then, the fungi were filled between adjacent anode and cathode plates to form an immobilized white-rot fungal layer. Electric field coupling operation: Connect wastewater containing new pollutants, turn on the DC regulated power supply, and set the operating parameters of the electric field control unit.

8. The method according to claim 7, characterized in that, The wastewater containing the new pollutants includes one or more of tetracycline, bisphenol A, ciprofloxacin, and estradiol.

9. The method according to claim 7, characterized in that, The bottom of the reactor is covered with a microporous titanium alloy aeration disc to provide sufficient dissolved oxygen to the water at a constant aeration rate of 0.2~1 L / min.

10. The method according to claim 7, characterized in that, The operating parameters of the electric field control unit are set as follows: voltage 1.5 V, power-on time 12 h per day, and plate spacing 5~8 cm.

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