Engineered electrode for electrobiocatalysis and process to construct the same

Abstract

The present disclosure provides a ready-to-use bio-electrode stable for long term storage and a process of constructing the same. The process for construction of bio-electrode for electro-biocatalysis comprising of: selection of an electro-active bacteria; enrichment of said electro-active bacteria in a nutrient rich medium; separation of said electro-active bacterial cells from said nutrient rich medium; selection of an electrode material; surface modification of said electrode material; layering the surface modified electrode material with conductive material; layering the surface modified electrode material with an electro-active bacterial cells along with biofilm inducing agents and stabilizing agents; conditioning the electro-active bacterial cells layered electrode; incubating the electrode obtained with an immobilizing agent along with conductive material; and conditioning the electrode with micronutrients to obtain a bio-electrode.

We claim: 
     
         1 . A bio-electrode for electro-biocatalysis, wherein said bio-electrode comprises:
 electro-active bacteria layered and immobilized on the modified surface of the electrode with an immobilizing agent and conductive material.   
     
     
         2 . The bio-electrode as claimed in  claim 1 , wherein the electro-active bacteria is selected from the group consisting of  Cupriavidus nector Ralstonia eutropha  DSMZ 428,  Geobacter hydrogenophilus  H-2 DSM 13691,  Methanobacterium palustre  DSMZ 3108,  Geobacter metallireducens  GS-15 DSMZ 7210,  Geobacter lovleyi  DSMZ 17278 , Geobacter sulfurrenducens  DSMZ 12127,  Shewanella putrefaciens  DSMZ 9471,  Shewanella putrefaciens  DSMZ 6067,  Shewanella putrefaciens  DSMZ 1818 , Acetobacterium woodi  DSM 1030,  Morella thermocetica  DSM 21394,  Clostridium aceticum  DSMZ 1496,  Clostridium ljungdahlii  DSM 13528 , Sporomusa sphaeroides  DSM 2875,  Sporomusa silvacetica  DSM 10669,  Cupriavidus nectar  DSM 529,  Sporomosa ovate  DSM 2662. 
     
     
         3 . The bio-electrode as claimed in  claim 1 , wherein the electro-active bacteria is selected from the group consisting of  Enterobacter aeronenes  MTCC 25016 , Serratia  sp. MTCC 25017,  Citrobacteer intermedius  MTCC 25018,  Pseudomonas aeruginosa  MTCC 25019,  Shewanella  sp. MTCC 25020,  Seudomonas stutzeri  MTCC 25027 or combinations thereof. 
     
     
         4 . The bio-electrode as claimed in  claim 1 , wherein the electrode is made of material selected from the group consisting of carbon cloth, stainless steel, flat graphite, flat copper, flat nickel, flat stainless steel, copper coated melamine foam, electron carbon fiber mat, carbonized corrugated card-board structures, graphite felt, activated carbon cloth, brush like anode made from carbon fibers, porous Ti 4 O 7  foam prepared by ice-templating, stainless steel felt, fluidized activated carbon particles, single activated carbon particles placed in an anode chamber, porous stainless steel filter membrane, buckypaper, carbon microfiber paper, carbon nano-fiber mat, poly(aniline-co-2,4-diaminnophenol) nanowire network on a carbon plate, polyaniline nanowire network a carbon plate, composite of PPy/anthraquinone-2,6-disulfonic disodium salt on carbon felt, compositer of MWCNTs and SnO 2  on a glassy carbon with PTFE binder, composite of polyaniline/mesoporous tungsten trioxide, graphite rods, graphite fiber brushes, graphite granules, stainless steel mesh, carbon felt, graphite granules, carbon cloth modified with reduced graphene oxide/tetraethylene pentamine, reticulated vitreous carbon, reticulated vitreous carbon modified with MWCNTs, stainless steel plate or a combination thereof. 
     
     
         5 . The bio-electrode as claimed in  claim 1 , wherein the immobilizing agent is selected from the group consisting of pectin, carboxymethylcellulose, propylene glycol; sodium carboxymethylcellulose, polyethylene glycol, hydroxyethylcellulose, alphacyclodextrin, locust bean gum or combinations thereof. 
     
     
         6 . The bio-electrode as claimed in  claim 1 , wherein the conducting material is selected from the group consisting of polymer poly(pyrrole)s (PPY), polycarbazoles, polyindoles, polyazepines, polyanilines (PANI) or combinations thereof. 
     
     
         7 . The bio-electrode as claimed in  claim 1 , wherein the bio-electrode has a shelf life of at least 2 years. 
     
     
         8 . A process of construction of bio-electrode, wherein said process comprises of:
 (a) selection of an electro-active bacteria;   (b) enrichment of said electro-active bacteria selected in step (a) in a nutrient rich medium;   (c) separation of said electro-active bacterial cells obtained in step (b) from said nutrient rich medium;   (d) selection of an electrode material;   (e) surface modification of said electrode material selected in step (d);   (f) layering the surface modified electrode material obtained in step (e) with conductive material and drying for 1-4 hours;   (g) layering the surface modified electrode material obtained in step (f) with an electro-active bacterial cells obtained in step (c) along with biofilm inducing agents and stabilizing agents;   (h) conditioning the electro-active bacterial cells layered electrode obtained in step (g);   (i) incubating the electrode obtained in step (h) with an immobilizing agent along with conductive material for 2-3 hours;   (j) conditioning the electrode obtained in step (i) with micronutrients to obtain a bio-electrode,   wherein said bio-electrode is having shelf-life of at least 2-3 years.   
     
     
         9 . The process as claimed in  claim 8 , wherein said electro-active bacteria in step (a) is selected from group consisting of  Cupriavidus nector Ralstonia eutropha  DSMZ 428 , Geobacter hydrogenophilus  H-2 DSM 13691,  Methanobacterium palustre  DSMZ 3108,  Geobacter metallireducens  GS-15 DSMZ 7210 , Geobacter lovleyi  DSMZ 17278 , Geobacter sulfurrenducens  DSMZ 12127,  Shewanella putrefaciens  DSMZ 9471,  Shewanella putrefaciens  DSMZ 6067,  Shewanella putrefaciens  DSMZ 1818 , Acetobacterium woodi  DSM 1030,  Morella thermocetica  DSM 21394,  Clostridium aceticum  DSMZ 1496,  Clostridium ljungdahlii  DSM 13528 , Sporomusa sphaeroides  DSM 2875,  Sporomusa silvacetica  DSM 10669,  Cupriavidus nectar  DSM 529,  Sporomosa ovate  DSM 2662;  Enterobacter aeronenes  MTCC 25016,  Serratia  sp. MTCC 25017 , Citrobacteer intermedius  MTCC 25018,  Pseudomonas aeruginosa  MTCC 25019,  Shewanella  sp. MTCC 25020,  Seudomonas stutzeri  MTCC 25027 or combinations thereof. 
     
     
         10 . The process as claimed in  claim 8 , wherein said nutrient rich medium in step (b) consists of yeast extract, peptone, mineral salts, vitamins and combinations thereof. 
     
     
         11 . The process as claimed in  claim 10 , wherein mineral salts are selected from the group consisting of NaHCO 3 , NH 4 Cl, NaH 2 PO 4 H 2 O, KCl, C 6 H 5 FeO 7  or combinations thereof. 
     
     
         12 . The process as claimed in  claim 7 , wherein said electrode material in step (d) is selected from the group consisting of carbon cloth, stainless steel, flat graphite, flat copper, flat nickel, flat stainless steel, copper coated melamine foam, electron carbon fiber mat, carbonized corrugated card-board structures, graphite felt, activated carbon cloth, brush like anode made from carbon fibers, porous Ti 4 O 7  foam prepared by ice-templating, stainless steel felt, fluidized activated carbon particles, single activated carbon particles placed in an anode chamber, porous stainless steel filter membrane, buckypaper, carbon microfiber paper, carbon nano-fiber mat, poly(aniline-co-2,4-diaminnophenol) nanowire network on a carbon plate, polyaniline nanowire network a carbon plate, composite of PPy/anthraquinone-2,6-disulfonic disodium salt on carbon felt, compositer of MWCNTs and SnO2 on a glassy carbon with PTFE binder, composite of polyaniline/mesoporous tungsten trioxide, graphite rods, graphite fiber brushes, graphite granules, stainless steel mesh, carbon felt, graphite granules, carbon cloth modified with reduced graphene oxide/tetraethylene pentamine, reticulated vitreous carbon, reticulated vitreous carbon modified with MWCNTs, stainless steel plate or a combination thereof. 
     
     
         13 . The process as claimed in  claim 8 , wherein said surface modification in step (e) is conducted by a treatment with agents selected from the group consisting of acid, base, heat, microwave, ultrasonic or combinations thereof. 
     
     
         14 . The process as claimed in  claim 8 , wherein said layering in steps (f) and (g) is conducted by procedures selected from a group consisting of mechanical layering, spraying, and dipping. 
     
     
         15 . The process as claimed in  claim 8 , wherein said stabilizing agents in step (g) are selected from the group consisting of norepinephrine, dopamine, alginate, polyglucosamine, colanic acid, cellulose, emulsan, chitosan, dextran, curdlan, kefiran, lentinan, pullulan or combinations thereof, and wherein inducing agents are selected from the group consisting of N-Butyryl-DL-homocysteine thiolactone, N-Butyryl-DL-homoserine lactone, N-(p-Coumaroyl)-L-homoserine lactone, N-Decanoyl-DL-homoserine lactone, N-Dodecanoyl-DL-homoserine lactone, cis-2-Dodecenoic acid, N-Heptanoyl-DL-homoserine lactone, 2-Heptyl-3-hydroxy-4(1H)-quinolone, N-Hexanoyl-DL-homoserine lactone, N-[(RS)-3-Hydroxybutyryl]-L-homoserine lactone, N-(3-Hydroxydodecanoyl)-DL-homoserine lactone, N-(3-Hydroxytetradecanoyl)-DL-homoserine lactone, N-(β-Ketocaproyl)-L-homoserine lactone, N-(β-Ketocaproyl)-DL-homoserine lactone, cis-11-Methyl-2-dodecenoic acid, N-Octanoyl-DL-homoserine lactone, N-(3-Oxododecanoyl)-L-homoserine lactone, N-(3-Oxooctanoyl)-DL-homoserine lactone, N-(3-Oxooctanoyl)-L-homoserine lactone, N-(3-Oxotetradecanoyl)-L-homoserine lactone, N-Tetradecanoyl-DL-homoserine lactone and a combination thereof. 
     
     
         16 . The process as claimed in  claim 8 , wherein said immobilizing agent in step (i) is selected from the group consisting of pectin, carboxymethylcellulose, propylene glycol, sodium carboxymethylcellulose, polyethylene glycol, hydroxyethylcellulose, alphacyclodextrin, locust bean gum or combinations thereof. 
     
     
         17 . The process as claimed in  claim 8 , wherein said conductive material in steps (f) and (i) is selected from the group consisting of polymer poly(pyrrole)s (PPY), polycarbazoles, polyindoles, polyazepines, polyanilines (PANI) or combinations thereof.