AN IN-SITU SYSTEM FOR ELECTRICITY GENERATION AND SOIL BIOREMEDIATION

Abstract

The present invention relates to bioelectrochemical systems and plant microbial fuel cells. Particularly, the present invention relates to an in-situ system that is capable of enhanced electricity generation and soil bioremediation using plant microbial fuel cells.

Specification

Description:FIELD OF INVENTION
The present invention in general relates to environmental biotechnology. Particularly, the present invention relates to bioelectrochemical systems and plant microbial fuel cells. More particularly, the present invention relates to an in-situ system that is capable of enhanced electricity generation and soil bioremediation using plant microbial fuel cells.

BACKGROUND OF INVENTION
Depletion of fossil fuels and the environmental issues related to their use has led to the exploitation of alternative sources of energy such as solar energy which is universal and reliable. The solar energy is usually employed to generate electricity using conventional photovoltaic cells. In recent years, other alternative bioelectrochemical systems such as plant microbial fuel cells (PMFCs) have been developed to generate electricity via biological interactions of plants and microbes in the presence of sunlight.
Compared to photovoltaic cells, PMFCs can also generate power continuously, being implemented on agricultural lands without any obstruction to food cultivation/production processes or even in fields unsuitable for food production. Plant microbial fuel cells (PMFCs) represent an innovative approach to generating bioelectricity by utilizing the symbiotic relationship between plants and microorganisms. These cells exploit the organic compounds released by plant roots into the soil, which are then metabolized by microbes to produce electrical energy. Recent advancements in PMFC technology have focused on optimizing various components such as electrode materials and microbial consortia to enhance their efficiency and power output. The plant's bioelectricity production capabilities are not well-documented, and most research in PMFCs has focused on species such as Arabidopsis thaliana or Zea mays.
Nitisoravut and Regmi et al., 2017 provide insight into the progress of PMFCs, factors affecting system performance, research achievement, challenges, and perspectives. Recently, Regmi et al., 2018 described the historical development of PMFCs and operational variables such as choice of plants, conductivity, pH, humidity, soil, and microbial health.
CN101908633B describes a plant-soil microbial fuel cell system that combines electricity-generating microbes and plant photosynthesis and CN108365245A describes a method for constructing a plant-microbial fuel cell.
F.T. Kabutey et al., 2019 describe the use of living plants for sustainable power generation in Plant microbial fuel cells. The review article also describes the various reported configurations of PMFCs embedded with vascular plants, macrophytes, and bryophytes as well as their combination with constructed wetlands. The document also describes the application of PMFCs in the fields of wastewater treatment, polluted sediment and surface water remediation, greenhouse gas mitigation, and biosensing.
Strik et al., 2008 proposed, developed, and proved the principle of plant sediment microbial fuel cell (PSMFC) as a result of the flux of organic matter (OM) at the anode during SMFC operation. By planting reed mannagrass (Glyceria maxima) at the anode of SMFC to utilize root exudate as OM by the EABs in the anolyte, it yielded a maximum power output of 67 mW m-2.
Although several studies have been conducted, however, none of these documents explored the applications of plant microbial fuel cell for simultaneous electricity generation and soil bioremediation. Accordingly, the present invention provides an in-situ system for the simultaneous generation of electricity and soil bioremediation, wherein the system is characterized in being provided with a plant capable of bioremediation.

SUMMARY OF THE INVENTION
This summary is provided to introduce a selection of concepts in a simplified format that are further described in the detailed description of the invention.
In an aspect of the present invention, there is provided an in-situ system for simultaneous generation of electricity and soil bioremediation, said system is characterized in being provided with a plant capable of bioremediation.
In an embodiment of the present invention, there is provided an in-situ system for simultaneous generation of electricity and soil bioremediation, wherein the system is provided with microbial fuel cell arrangement comprising an anode positioned in an anodic chamber; a cathode positioned in a cathodic chamber; and a proton exchange membrane.
In another embodiment of the present invention, there is provided an in-situ system for simultaneous generation of electricity and soil bioremediation, wherein the anode in an anodic chamber is submerged anode in contact with soil present in-situ system.
In yet another embodiment of the present invention, there is provided an in-situ system for simultaneous generation of electricity and soil bioremediation, wherein the cathode in the cathodic chamber is an open-air cathode.
In still another embodiment of the present invention, there is provided an in-situ system for simultaneous generation of electricity and soil bioremediation, wherein the anode and cathode are connected by an external circuit.
In an embodiment of the present invention, there is provided an in-situ system for simultaneous generation of electricity and soil bioremediation, wherein the plant is selected from Brassica juncea, Cicer arietinum, Zea mays and Brassica napus.
In another embodiment of the present invention, there is provided an in-situ system for simultaneous generation of electricity and soil bioremediation, wherein the plant is Brassica napus.
In still another embodiment of the present invention, there is provided an in-situ system for simultaneous generation of electricity and soil bioremediation, wherein the plant is grown in the anodic chamber, and wherein the roots of the plant interact with microbes present in soil.
In yet another embodiment of the present invention, there is provided an in-situ system for simultaneous generation of electricity and soil bioremediation, wherein the microbes are electroactive bacteria selected from Pseudomonas sp. and Bacillus sp.
In an embodiment of the present invention, there is provided an in-situ system for simultaneous generation of electricity and soil bioremediation, wherein the anode and cathode are made up of carbon cloth.
These and other features, aspects, and advantages of the present invention will become better understood with reference to the following description and appended claims. This summary is provided to introduce a selection of concepts in a simplified form. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.

BRIEF DESCRIPTION OF THE DRAWINGS:
These and other features, aspects, and advantages of the present disclosure will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein:
Figure 1 illustrates the schematic diagrammatic representation of the bioremediation and electricity production by plant microbial fuel cell.
Figure 2 illustrates the polarization study conducted for plant microbial fuel with (i) soil and (ii) nutrient enriched soil.
Figure 3 illustrates the cyclic voltammetry study of the plant microbial fuel cell with (i) soil and (ii) nutrient enriched soil.

DETAILED DESCRIPTION OF THE INVENTION:
While the invention is susceptible to various modifications and alternative forms, specific embodiment thereof will be described in detail below. It should be understood, however that it is not intended to limit the invention to the particular forms disclosed, but on the contrary, the invention is to cover all modifications, equivalents, and alternative falling within the scope of the invention as defined by the appended claims.
Those skilled in the art will be aware that the present invention is subject to variations and modifications other than those specifically described. It is to be understood that the present invention includes all such variations and modifications. The disclosure also includes all such steps of the process, features of the invention, referred to or indicated in this specification, individually or collectively, and any and all combinations of any or more of such steps or features.
Definitions
For convenience, before further description of the present invention, certain terms employed in the specification, and examples are collected here. These definitions should be read in the light of the remainder of the disclosure and understood as by a person skilled in the art. The terms used herein have the meanings recognized and known to those of skill in the art, however, for convenience and completeness, particular terms and their meanings are set forth below.

For the purpose of promoting an understanding of the principles of the disclosure, reference will now be made to the embodiment illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the disclosure is thereby intended, such alterations and further modifications in the illustrated system, and such further applications of the principles of the disclosure as illustrated therein being contemplated as would normally occur to one skilled in the art to which the disclosure relates. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skilled in the art to which this disclosure belongs. The system, methods, and examples provided herein are illustrative only and not intended to be limiting.
Although any methods and materials similar or equivalent to those described herein can also be used in the practice or testing of the present disclosure, the preferred methods and materials are now described. All publications mentioned herein are incorporated herein by reference to disclose and describe the methods and/or materials in connection with which the publications are cited.
It must be noted that as used herein and in the appended claims, the singular forms "a", "and", and "the" include plural referents unless the context dictates otherwise. Thus, for example, reference to "a compound" includes a plurality of such compounds, and reference to "the step" includes reference to one or more steps and equivalents thereof known to those skilled in the art, and so forth.
The term "some" as used herein is defined as "none, or one, or more than one, or all." Accordingly, the terms "none," "one," "more than one," "more than one, but not all" or "all" would all fall under the definition of "some." The term "some embodiments" may refer to no embodiments or to one embodiment or to several embodiments or to all embodiments. Accordingly, the term "some embodiments" is defined as meaning "no embodiment, or one embodiment, or more than one embodiment, or all embodiments."
The terminology and structure employed herein is for describing, teaching and illuminating some embodiments and their specific features and elements and does not limit, restrict or reduce the spirit and scope of the claims or their equivalents.
More specifically, any terms used herein such as but not limited to "includes", "comprises", "has", "consists" and grammatical variants thereof is inclusive or open-ended and does not exclude additional, unrecited elements or method steps. The specification will be understood to also include embodiments which have the transitional phrase "consisting of" or "consisting essentially of" in place of the transitional phrase "comprising." The transitional phrase "consisting of" excludes any element, step, or ingredient not specified in the claim, except for impurities associated therewith. The transitional phrase "consisting essentially of" limits the scope of a claim to the specified materials or steps "and those that do not materially affect the basic and novel characteristic(s)" of the claimed disclosure.
As used in the specification, "in-situ" refers to "on-site" or "in position".

As used in the specification, "bioremediation" refers to any process wherein a biological system (typically bacteria, microalgae, fungi, and plants, living or dead, is employed for removing environmental pollutants from air, water, soil, flue gasses, industrial effluents, etc., in natural or artificial settings.

As used in the specification, a microbial fuel cell (MFC) is a device that converts chemical energy to electrical energy by the action of microorganisms.

The present invention provides an in-situ system for the simultaneous generation of electricity and soil bioremediation. The in-situ system is characterized in being provided with plants capable of bioremediation. Specifically, the system comprises a plant microbial fuel cell (p-MFCs) for the dual purposes of bioelectricity generation and soil bioremediation. The present invention harnesses the natural processes occurring at the root-soil interface. The plant Brassica napus interacts with soil microorganisms to exude organic compounds that serve as substrates for microbial oxidation. This microbial activity is crucial for the generation of electrons, which are captured and transferred through the fuel cell system to produce electricity. The strategic integration of this plant in p-MFCs aims to enhance the efficiency and output of bioelectricity, leveraging its robust root system and the prolific exudation of organic materials that fuel microbial metabolism and electron transfer processes. Further, the present invention addresses significant environmental concerns by employing the same microbial processes for bioremediation. The soil microbes associated with the roots of Brassica napus play a critical role in degrading organic pollutants, thus cleaning up contaminated soils while simultaneously contributing to the bioelectricity generation process. This dual functionality makes the present invention a valuable advancement in the pursuit of eco-friendly technologies that address both energy production and environmental sustainability. The in-situ system disclosed in the present invention can be deployed in various settings, including agricultural fields, industrial sites, and urban areas, providing a versatile solution to energy and environmental challenges.
Thus, in accordance with the present invention, there is provided an in-situ system for simultaneous generation of electricity and soil bioremediation, said system is characterized in being provided with a plant capable of bioremediation.
In an embodiment of the present invention, there is provided an in-situ system for simultaneous generation of electricity and soil bioremediation, wherein the system is provided with microbial fuel cell arrangement comprising an anode positioned in an anodic chamber; a cathode positioned in a cathodic chamber; and a proton exchange membrane.
In another embodiment of the present invention, there is provided an in-situ system for simultaneous generation of electricity and soil bioremediation, wherein the anode in an anodic chamber is submerged anode in contact with soil present in-situ system.
In yet another embodiment of the present invention, there is provided an in-situ system for simultaneous generation of electricity and soil bioremediation, wherein the cathode in the cathodic chamber is an open-air cathode.
In still another embodiment of the present invention, there is provided an in-situ system for simultaneous generation of electricity and soil bioremediation, wherein the anode and cathode are connected by an external circuit.
In an embodiment of the present invention, there is provided an in-situ system for simultaneous generation of electricity and soil bioremediation, wherein the plant is selected from Brassica juncea, Cicer arietinum, Zea mays and Brassica napus. In a preferred embodiment of the present invention, the plant is Brassica napus.
In another embodiment of the present invention, there is provided an in-situ system for simultaneous generation of electricity and soil bioremediation, wherein the plant is grown in the anodic chamber, and wherein the roots of the plant interact with microbes present in soil.
In yet another embodiment of the present invention, there is provided an in-situ system for simultaneous generation of electricity and soil bioremediation, wherein the microbes are electroactive bacteria selected from Pseudomonas species and Bacillus species.
In still another embodiment of the present invention, there is provided an in-situ system for simultaneous generation of electricity and soil bioremediation, wherein the anode and cathode are made up of carbon cloth.
Advantages of Present Invention
The present invention addresses critical global challenges i.e., sustainable energy production and environmental pollution.
Sustainable Energy Production: As the traditional energy sources, such as fossil fuels, are finite and contribute significantly to environmental degradation and climate change, thus, the present invention provides a renewable and eco-friendly energy solution by harnessing the natural processes of Brassica napus and soil microbes to generate bioelectricity.
Environmental Pollution: The present invention utilizes the bioremediation potential of Brassica napus 's rhizosphere, where root-associated microbes degrade organic pollutants, thereby cleaning the soil while contributing to the generation of electricity. This dual-function approach not only mitigates pollution but also enhances the overall efficiency of the microbial fuel cell system.
EXAMPLES
The disclosure will now be illustrated with working examples, which is intended to illustrate the working of disclosure and not intended to take restrictively to imply any limitations on the scope of the present disclosure. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood to one of ordinary skill in the art to which this disclosure belongs. The following examples are set forth below to illustrate the microbial electrosynthesis systems for the production of organic compounds by the application of electricity in the presence of biocatalysts. These examples are not intended to be inclusive of all aspects of the subject matter disclosed herein, but rather to illustrate representative product and results. These examples are not intended to exclude equivalents and variations of the present invention, which are apparent to one skilled in the art.
Example 1: Microbial Fuel Cell Configuration and Operation
To configure and operate a microbial fuel cell (MFC) with Brassica napus for bioelectricity production and bioremediation, the plant is grown in the anode chamber where its roots interact with soil and a microbial community consisting of Pseudomonas sp., and Bacillus sp., releasing organic compounds and microbes, producing electrons and protons metabolize these compounds. The electrons are captured by a submerged anode electrode with a surface area of 16 cm X 12 cm, and flow through an external circuit to the cathode of 16 cm X 12 cm, generating electricity. At the same time, protons combine with electrons and an electron acceptor, typically oxygen, to form water in the cathode area. This setup not only generates power but also leverages microbial activity to degrade contaminants in the soil, enhancing bioremediation. The plant roots release organic exudates into the soil, which microbes metabolize, generating electrons and protons. Electroactive bacteria like Pseudomonas sp. transfer electrons to the anode, forming a biofilm. These electrons flow through an external circuit to the cathode, generating electricity, while protons migrate through a proton exchange membrane (PEM) to the cathode chamber. At the cathode, electrons, protons, and oxygen combine to form water, completing the circuit. Simultaneously, the microbial community degrades contaminants, enhancing bioremediation while maintaining bioelectricity production.
Example 2: Polarization study and electrochemical analysis of Microbial Fuel Cell
Polarization studies in microbial fuel cells investigate the performance by assessing the voltage-current relationship to identify optimal conditions for operation. In polarization study, volumetric power density is the power output per unit volume of the reactor and helps in the assessment of the efficiency and scalability of the MFCs. Using a resistance box, the resistance across the cell was lowered from 100kO to 10O in decreasing sequence to obtain polarization curves. Current density is measured with a digital multimeter. A Biologic SP-150 data recorder was used to conduct the polarization experiment.
P_d= EI/V
The volumetric power density (Pd (W/m3) was computed by solving the following equation, where I denotes current flowing through the loads and E denotes voltage. The anolyte's volume is V.
Cyclic voltammetry (CV) is a reliable electrochemical technique for examining the reduction and oxidation processes of molecular species. Cyclic voltammetry (CV) is frequently employed to enhance the comprehension of catalysis and other chemical reactions necessitating the first transfer of electrons. A reference solution, an electrolyte solution, three electrodes, and an electrochemical cell are required for cyclic voltammetry. Next, using a potentiostat, the difference in voltage between the reference electrode and the working electrode needs to be continuously observed. The potentiostat performs this function multiple times while scanning. The experimental setup made use of the Ag/AgCl reference electrode. The potentials were scanned between -1V and 1V at a rate of 1mV/s.
Example 3: Simultaneous Bioremediation and Electricity generation by Plant Microbial Fuel Cell
The present study aimed to evaluate the effectiveness of nutrient-rich fruit waste in remediating heavy metal contaminants, specifically lead (Pb) and cadmium (Cd), in soil. To conduct the experiment, 3 kg of enriched soil was prepared, incorporating 15% fruit waste, such as banana and apple peels, which are known for their organic content and nutrient properties. Brassica napus seeds were planted to promote root growth and microbial activity, thereby enhancing the bioremediation process. Contaminated mineral solutions containing known concentrations of lead and cadmium were mixed into the soil. The solutions were prepared with initial concentrations of 100 mg/L for lead and 50 mg/L for cadmium. After equilibrating the contaminated soil for 24 hours, the Brassica napus plants were cultivated under controlled conditions with adequate light, temperature, and moisture to support growth and microbial interactions.
Throughout a 30-day period, soil samples were collected at regular intervals (days 7, 14, 21, and 30) to assess the concentration of heavy metals. These samples underwent a preparatory process involving the addition of a complexing agent, such as EDTA, which reacted with lead and cadmium to form detectable complexes. The resulting solutions were analyzed using a UV spectrophotometer, measuring absorbance at specific wavelengths associated with the metal complexes.
The results indicated a significant reduction in heavy metal concentrations throughout the study, with lead levels anticipated to decrease from 100 mg/L to approximately 25 mg/L and cadmium levels from 50 mg/L to about 5 mg/L. UV spectroscopy measurements correlated with these reductions, confirming the effective degradation and uptake of heavy metals.
In terms of electricity generation (as indicated in Example 2), the polarization curves for both the MFCs are shown in Figure 2. From the Figure, it can be concluded that the plant microbial fuel cell (p-MFC) with enriched soil shows a better result rather than the p-MFC with soil only. The cyclic voltammetry study shows significant oxidation and reduction peaks in both the MFCs (as shown in Figure 3.)
, Claims:1. An in-situ system for simultaneous generation of electricity and soil bioremediation, said system is characterized in being provided with a plant capable of bioremediation.

2. The system as claimed in claim 1, wherein the system is provided with microbial fuel cell arrangement comprising an anode positioned in an anodic chamber; a cathode positioned in a cathodic chamber; and a proton exchange membrane.

3. The system as claimed in claims 1-2, wherein the anode in an anodic chamber is submerged anode in contact with soil present in-situ system.

4. The system as claimed in claims 1-3, wherein the cathode in the cathodic chamber is an open-air cathode.

5. The system as claimed in claims 1-4, wherein the anode and cathode are connected by an external circuit.

6. The system as claimed in claim 1, wherein the plant is selected from Brassica juncea, Cicer arietinum, Zea mays and Brassica napus.

7. The system as claimed in claim 6, wherein the plant is Brassica napus.

8. The system as claimed in claims 1-7, wherein the plant is grown in the anodic chamber, and wherein the roots of the plant interact with microbes present in soil.

9. The system as claimed in claim 8, wherein the microbes are electroactive bacteria selected from Pseudomonas species and Bacillus species.

10. The system as claimed in claims 1-9, wherein the anode and cathode are made up of carbon cloth.

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