# US 11,111,509 B2 · Bio-assisted process for conversion of mixed volatile fatty acids to selective drop-in fuels

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- Number: US 11,111,509 B2
- Document ID: US11111509B2
- Status: Granted
- Kind: B2
- Application number: 16/353,666
- Filed: 2019-03-14
- Published: 2019-09-19
- Granted: 2021-09-07
- Earliest claimed: 2018-03-15
- Assignees: Indian Oil Corporation Limited
- Applicants: Indian Oil Corporation Limited
- Inventors: Manoj Kumar; Sandipam Srikanth; Dheer Singh; Suresh Kumar Puri; Sankara Sri Venkata Ramakumar
- Web page: https://patentgrep.com/patent/US11111509B2

## CPC

- C12P 7/14: Multiple stages of fermentation; Multiple types of microorganisms or re-use of microorganisms
- C10L 1/02: essentially based on components consisting of carbon, hydrogen, and oxygen only
- C12P 7/02: containing a hydroxy group
- C12P 7/04: acyclic
- C12P 7/065: {with microorganisms other than yeasts}
- C12P 7/52: Propionic acid; Butyric acids
- C12P 7/54: Acetic acid (vinegar C12J)
- C25B 3/07: Oxygen containing compounds
- C25B 3/25: Reduction
- C25B 9/70: Assemblies comprising two or more cells
- C25B 11/043: Carbon, e.g. diamond or graphene
- C10L 2200/0484: Vegetable or animal oils
- C10L 2290/26: Composting, fermenting or anaerobic digestion fuel components or materials from which fuels are prepared
- C10L 2290/38: Applying an electric field or inclusion of electrodes in the apparatus
- Y02E 50/10: Biofuels, e.g. bio-diesel
- C12P: FERMENTATION OR ENZYME-USING PROCESSES TO SYNTHESISE A DESIRED CHEMICAL COMPOUND OR COMPOSITION OR TO SEPARATE OPTICAL ISOMERS FROM A RACEMIC MIXTURE {(brewing of beer C12C; producing vinegar C12J; producing specific peptides or proteins C07K; producing enzymes C12N9/00; DNA or RNA concerning genetic engineering, vectors, e.g. plasmids, or their isolation, preparation or purification C12N15/00; measuring or testing processes involving enzymes or microorganisms C12Q; measuring or testing processes involving nucleic acid amplification reactions C12Q1/6844; fermentation processes to form a food composition, A21 or A23; compounds in general, see the relevant compound class, e.g. C01, C07)}
- C10L: FUELS NOT OTHERWISE PROVIDED FOR; NATURAL GAS; SYNTHETIC NATURAL GAS OBTAINED BY PROCESSES NOT COVERED BY SUBCLASSES C10G OR C10K; LIQUIFIED PETROLEUM GAS; USE OF ADDITIVES TO FUELS OR FIRES; FIRE-LIGHTERS
- C25B: ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR (anodic or cathodic protection C23F13/00; single-crystal growth C30B)
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

The present invention relates to a two-stage process for production of drop-in fuels/alcohols (methanol, ethanol or butanol) from volatile fatty acids produced either synthetically from fossil resources or as metabolic intermediates in acidification step of anaerobic digestion process from waste biomass and organic materials.

## Claims

### Claim 1

A bio-assisted process for production of drop-in fuels from CO2 and a volatile fatty acid rich source, said process comprising:
(a) providing a first electrochemical system comprising at least one working electrode, at least one counter electrode, and a medium inoculated with selectively enriched electro-active bacteria selected from the group consisting of Geobacter anodireducens, Clostridium ljungdahlii, Acetobacterium woodii, Sporomusa acidovorans, Propionibacterium acidifaciens, Acetobacterium carbinolicum, Pseudomonas stutzeri MTCC 25027, Pseudomonas fragi MTCC 25025, Pseudomonas aeruginosa MTCC 5389, Psuedomonas alcaligenes, Schewanella putrefaciens, Clostridium aciditolerans, Enterobacter aerogenes MTCC 25016, Shewanella sp. MTCC 25020, and combinations thereof;
(b) providing feedstock to the first electrochemical system of step (a), wherein the feedstock comprises CO2 with the volatile fatty acid rich source;
(c) intensifying carboxylic acids in the feedstock of step (b) to obtain an effluent comprising intensified carboxylic acids;
(d) providing a second electrochemical system comprising at least one working electrode, at least one counter electrode, and a medium inoculated with selectively enriched electro-active bacteria selected from the group consisting of Sporomusa ovate, Clostridium acetobutylicum, Clostridium butyricum, Clostridium acidurici, Pseudomonas aeruginosa MTCC 5388, Pseudomonas putida MTCC 5387, Clostridium carboxidivorans, Clostridium beijerinckii, Schewanella oneidensis, Geobacter sdfurreducens, Clostridium cellutolyticum, Clostridium cellulosi, Clostridium cellulovorans, Alicaligens sp. MTCC 25022, Serratia sp. MTCC 25017, Lysinibacillus sp. MTCC 5666, and combinations thereof; and
(e) reducing the intensified carboxylic acids of step (c) in the second electrochemical system to obtain the drop-in fuels;
wherein the working electrode of the first electrochemical system is composed of a material selected from the group consisting of graphite plate, carbon brush, carbon paper, graphite felt, activated carbon cloth, and combinations thereof;
wherein the counter electrode of the first electrochemical system is modified with a material selected from the group consisting of carbon nanotube (CNT), graphene, charcoal, activated carbon, stainless steel (SS) mesh, nickel oxide, zinc oxide, and iron oxide;
wherein the volatile fatty acid rich source comprises at least 0.5% formic acid, provided that if the formic acid is not already present in the feedstock the feedstock is supplemented with at least 0.5% formic acid;
wherein the working electrode of the second electrochemical system is composed of a material selected from the group consisting of graphite plate, graphite rod, carbon brush, carbon paper, carbon plate, graphite felt, activated carbon cloth, and combinations thereof; and
wherein the counter electrode of the second electrochemical system is modified with a material selected from the group consisting of CNT, Co9S8, graphene, FTO/NiO, Ni/Fe layered double hydroxide, Si/TiO2 nanowires, charcoal, activated carbon, nickel oxide, zinc oxide, and iron oxide; and
wherein the drop-in fuels are selected form the group consisting of methanol, ethanol, butanol, acetic acid, propanoic acid, butanoic acid, valeric acid, and caproic acid.

### Claim 2 (depends on 1)

The bio-assisted process as claimed in claim 1, wherein the first electrochemical system is operated at a temperature ranging from 20° C. to 50° C.

### Claim 3 (depends on 1)

The bio-assisted process as claimed in claim 1, wherein the first electrochemical system is operated at a pH ranging from 6.5 to 9.0.

### Claim 4 (depends on 1)

The bio-assisted process as claimed in claim 1, wherein the first electrochemical system is operated at an applied potential ranging from 1V to 4V.

### Claim 5 (depends on 1)

The bio-assisted process as claimed in claim 1, wherein the working electrode of the second electrochemical system is modified with a material selected from the group consisting of CNT, graphene, activated charcoal, noble metal, composite of Zr or Ti or Cd or Fe, metal-free alloy, metal carbide, phosphide, and nickel oxide, zinc oxide, iron oxide, metal-phosphorous alloy, metal-sulfur alloy, metal organic framework, and combinations thereof.

### Claim 6 (depends on 1)

The bio-assisted process as claimed in claim 1, wherein the carboxylic acid in step (c) has a length ranging from C2 to C6.

### Claim 7 (depends on 1)

The bio-assisted process as claimed in claim 1, wherein the second electrochemical system is operated at a temperature ranging from 20° C. to 50° C.

### Claim 8 (depends on 1)

The bio-assisted process as claimed in claim 1, wherein the second electrochemical system is operated at a pH ranging from 4.0 to 6.0.

### Claim 9 (depends on 1)

The bio-assisted process as claimed in claim 1, wherein the second electrochemical system is operated at an applied potential ranging from 2V to 6V.

### Claim 10 (depends on 1)

The bio-assisted process as claimed in claim 1, wherein the volatile fatty acid rich source is selected from the group consisting of kitchen waste, biomass waste, agricultural waste, biodegradable municipal waste, lignocellulosic waste, and de-oiled algal cake.

### Claim 11 (depends on 1)

The bio-assisted process as claimed in claim 1, wherein the reduction of carboxylic acids in step (e) is carried out in presence of a redox shuttler selected from the group consisting of neutral red, methylene blue, phenazine derivative, iron based metal complex, nickel based metal complex, zinc based metal complex, anthraquinone-2,6-disulfonate (AQDS), and combinations thereof.