# US 9,518,248 B2 · Optofluidic photobioreactor apparatus, method, and applications

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- Number: US 9,518,248 B2
- Document ID: US9518248B2
- Status: Granted
- Kind: B2
- Application number: 13/885,478
- Filed: 2011-11-14
- Published: 2013-11-14
- Granted: 2016-12-13
- Earliest claimed: 2010-11-15
- Assignees: Cornell University
- Applicants: David Erickson; David Sinton
- Inventors: David Erickson; David Sinton
- Web page: https://patentgrep.com/patent/US9518248B2

## CPC

- C12M 31/08: {by conducting or reflecting elements located inside the reactor or in its structure}
- C12M 21/02: {Photobioreactors (culturing algae A01G33/00, A01H4/001, C12N1/12)}
- C12M 31/02: {located outside the reactor}
- C12M 31/10: {by light emitting elements located inside the reactor, e.g. LED or OLED}
- C12P 7/04: acyclic
- C12P 7/065: {with microorganisms other than yeasts}
- G02B 6/00: Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B 6/262: {Optical details of coupling light into, or out of, or between fibre ends, e.g. special fibre end shapes or associated optical elements}
- G02B 6/29331: {operating by evanescent wave coupling}
- C10L 1/02: essentially based on components consisting of carbon, hydrogen, and oxygen only
- C12N 1/12: Unicellular algae; Culture media therefor (as new plants A01H13/00)
- C12N 1/20: Bacteria; Culture media therefor
- C12P 7/24: containing a carbonyl group
- Y02E 50/10: Biofuels, e.g. bio-diesel
- Y02E 50/30: Fuel from waste, e.g. synthetic alcohol or diesel
- C12M: APPARATUS FOR ENZYMOLOGY OR MICROBIOLOGY; {APPARATUS FOR CULTURING MICROORGANISMS FOR PRODUCING BIOMASS, FOR GROWING CELLS OR FOR OBTAINING FERMENTATION OR METABOLIC PRODUCTS, i.e. BIOREACTORS OR FERMENTERS}
- 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)}
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- 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
- C12N: MICROORGANISMS OR ENZYMES; COMPOSITIONS THEREOF; PROPAGATING, PRESERVING, OR MAINTAINING MICROORGANISMS; MUTATION OR GENETIC ENGINEERING; CULTURE MEDIA (microbiological testing media C12Q1/00)
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

An optofluidic photobioreactor including an optical waveguide having an input, characterized by an evanescent optical field confined along an outer surface of the optical waveguide produced by radiation propagating in the optical waveguide, means for inputting light to the input of the optical waveguide, and a selected photosynthetic microorganism disposed substantially within the evanescent field. A method for optically exciting a photosynthetic microorganism for generating a biofuel, a biofuel precursor, or a biomass from the optically-excited photosynthetic microorganism involves irradiating the photosynthetic microorganism attached to the surface of the waveguide with an evanescent optical field from optical radiation propagating in the optical waveguide, and driving photosynthesis in the microorganism by the evanescent optical field.

## Claims

### Claim 1

An optofluidic photobioreactor, comprising:
an optical waveguide having an input, characterized by an evanescent optical field confined along an outer surface of the optical waveguide produced by radiation propagating in the optical waveguide;
means for inputting light to the input of the optical waveguide; and
a selected photosynthetic microorganism disposed substantially within the evanescent field, wherein the selected photosynthetic microorganism is in the form of an adsorbed single layer of the microorganism.

### Claim 2 (depends on 1)

The photobioreactor of claim 1, wherein the optical waveguide is an unclad optical fiber having a diameter, d, where 10 μm<d<100 μm, and an input end.

### Claim 3 (depends on 2)

The photobioreactor of claim 2, wherein the optical waveguide is a multi-mode optical fiber.

### Claim 4 (depends on 2)

The photobioreactor of claim 2, further comprising a plurality of optical waveguides disposed in a side-by-side array configuration and having a center-to-center intra-waveguide separation, D, where d<D<1.5d.

### Claim 5 (depends on 4)

The photobioreactor of claim 4, further comprising a photobioreactor enclosure having an input and an output, inside of which the plurality of optical waveguides are disposed, wherein the photobioreactor enclosure is characterized by a plurality of optically-dark fluid channels created by a void space surrounding the plurality of optical waveguides.

### Claim 6 (depends on 5)

The photobioreactor of claim 5, further comprising a liquid microorganism-nutrient media disposed in the void space.

### Claim 7 (depends on 5)

The photobioreactor of claim 5, further comprising a controller operably connected to the photobioreactor enclosure.

### Claim 8 (depends on 1)

The photobioreactor of claim 1, wherein the optical waveguide further comprises a prism waveguide.

### Claim 9 (depends on 8)

The photobioreactor of claim 8, wherein the means for inputting light to the input of the optical waveguide comprises a laser output directly input to the prism waveguide.

### Claim 10 (depends on 1)

The photobioreactor of claim 1, wherein the means for inputting light to the input of the optical waveguide comprises solar radiation channeled to the input of the optical waveguide.

### Claim 11 (depends on 1)

The photobioreactor of claim 1, wherein the photosynthetic microorganism is at least one of a bacterium and algae.

### Claim 12 (depends on 11)

The photobioreactor of claim 11, wherein the bacterium is a cyanobacterium.

### Claim 13 (depends on 12)

The photobioreactor of claim 12, wherein the cyanobacterium is Synechococcus.

### Claim 14 (depends on 13)

The photobioreactor of claim 13, wherein the cyanobacterium is Synechococcus elongatus.

### Claim 15 (depends on 1)

The photobioreactor of claim 1, wherein the photosynthetic microorganism is a genetically-engineered, direct biofuel-producing microorganism.

### Claim 16 (depends on 1)

The photobioreactor of claim 1, further comprising a microfluidic chip in or on which a plurality of the optical waveguides are disposed.

### Claim 17 (depends on 16)

The photobioreactor of claim 16, wherein the microfluidic chip is in the form of a high aspect ratio (thin) sheet.

### Claim 18 (depends on 17)

The photobioreactor of claim 17, wherein the high aspect ratio (thin) sheet is corrugated.

### Claim 19 (depends on 1)

The photobioreactor of claim 1, wherein the optical waveguide is a sheet waveguide.

### Claim 20 (depends on 19)

The photobioreactor of claim 19, wherein the sheet waveguide is corrugated.

### Claim 21 (depends on 1)

The photobioreactor of claim 1, further comprising an artificial adhesive disposed intermediate the outer surface of the waveguide and the selected photosynthetic microorganism such that the microorganism is adhered to the outer surface of the waveguide.

### Claim 22

A method for optically exciting a photosynthetic microorganism for generating a biofuel, a biofuel pre-cursor, or a biomass from the optically-excited photosynthetic microorganism, comprising:
providing an optical waveguide having an outer surface;
inputting optical radiation to the optical waveguide;
propagating the optical radiation in the optical waveguide;
generating an evanescent optical field adjacent the outer surface of the optical waveguide from the optical radiation propagating in the optical waveguide;
providing a photosynthetic microorganism within the evanescent optical field of the optical waveguide, wherein the selected photosynthetic microorganism is in the form of an adsorbed single layer of the microorganism; and
driving photosynthesis in the microorganism by irradiating at least a portion of a thylakoid membrane of the photosynthetic microorganism with the evanescent optical field.

### Claim 23 (depends on 22)

The method of claim 22, wherein the step of providing an optical waveguide further comprises providing a prism waveguide.

### Claim 24 (depends on 23)

The method of claim 23, wherein the step of inputting optical radiation to the optical waveguide further comprises directly injecting light from a laser into the prism waveguide in a manner to propagate the light by total internal reflection.

### Claim 25 (depends on 24)

The method of claim 24, further comprising injecting light in a wavelength range 600 nm<λ<700 nm.

### Claim 26 (depends on 22)

The method of claim 22, wherein the step of providing a photosynthetic microorganism within the evanescent optical field of the optical waveguide further comprises providing the photosynthetic microorganism adjacent the outer surface of the optical waveguide in a region extending not more than about five microns (5 μm) from the outer surface of the optical waveguide.

### Claim 27 (depends on 22)

The method of claim 22, further comprising:
providing a plurality of the optical waveguides disposed in a side-by-side array configuration;
providing a photobioreactor enclosure having an input and an output, inside of which the plurality of optical waveguides are disposed, wherein the photobioreactor enclosure is characterized by a plurality of optically-dark fluid channels created by a void space surrounding the plurality of optical waveguides;
providing a microorganism nutrient media in the plurality of optically-dark fluid channels; and
harvesting a biofuel, a biofuel pre-cursor, or a biomass from the photobioreactor enclosure output.

### Claim 28 (depends on 27)

The method of claim 27, wherein the step of providing a photosynthetic microorganism further comprises providing a free-floating microorganism media within the enclosure.

### Claim 29 (depends on 27)

The method of claim 27, further comprising providing a suitable photosynthetic microorganism and directly harvesting a biofuel from the photobioreactor.

### Claim 30 (depends on 27)

The method of claim 27, further comprising providing a suitable photosynthetic microorganism and harvesting a biofuel precursor from the photobioreactor.

### Claim 31 (depends on 27)

The method of claim 27, further comprising providing a suitable photosynthetic microorganism and harvesting a biomass from the photobioreactor.

### Claim 32 (depends on 22)

The method of claim 22, further comprising inputting solar optical radiation to the optical waveguide.

### Claim 33 (depends on 22)

The method of claim 22, further comprising providing a controller and controlling a parameter of the optical radiation input to the optical waveguide.