Algae bioreactor using submerged enclosures with semi-permeable membranes

• US 20100216203A1
• Filed: 12/05/2008
• Published: 08/26/2010
• Est. Priority Date: 12/05/2008
• Status: Active Grant

• Current Assignee: SETI Institute, USA As Represented By The Administrator Of The NASA
• Original Assignee: USA As Represented By The Administrator Of The NASA
• Inventors: Gormly, Sherwin J., Trent, Jonathan D., Flynn, Michael T., Embaye, Tsegereda N., Delzeit, Lance D.
• Granted Patent: US 8,409,845 B2
• Time in Patent Office: Days
• US Class Current: 435/166
• CPC Class Codes: A01G 33/00 Cultivation of seaweed or algae
• CPC Class Codes: C12M 21/02 Photobioreactors culturing algae A01G33/00, A01H4/001, C12N1/12
• CPC Class Codes: C12M 23/14 Bags
• CPC Class Codes: C12M 23/26 flexible flexible containers for laboratory use B01L3/505
• CPC Class Codes: C12M 23/56 Floating elements
• CPC Class Codes: C12M 47/02 Separating microorganisms from the culture medium; Concentration of biomass separating microorganisms from their culture media C12N1/02
• CPC Class Codes: Y02A 40/80 in fisheries management
• CPC Class Codes: Y02P 60/20 Reduction of greenhouse gas [GHG] emissions in agriculture, e.g. CO2

Abstract

Methods for producing hydrocarbons, including oil, by processing algae and/or other micro-organisms in an aquatic environment. Flexible bags (e.g., plastic) with CO₂/O₂ exchange membranes, suspended at a controllable depth in a first liquid (e.g., seawater), receive a second liquid (e.g., liquid effluent from a “dead zone”) containing seeds for algae growth. The algae are cultivated and harvested in the bags, after most of the second liquid is removed by forward osmosis through liquid exchange membranes. The algae are removed and processed, and the bags are cleaned and reused.

Claims

1. A method for producing at least one hydrocarbon product, the method comprising:

providing a sealable bag, made of a selected bag material, having a bag interior, and being defined by a first and second opposed bag surfaces that are joined together, where the first bag surface comprises (i) a first sequence of membrane patches that permit exchange of CO₂ and O₂ across the first sequence of membrane patches and (ii) a second sequence of membrane patches that are permeable to liquid of a first type and are substantially impermeable to at least one selected micro-organism (“

μ

org”

);

positioning the bag in a body of liquid of the first type, adjacent to a surface thereof, with the bag first surface being closest to the liquid surface, between the first liquid surface and the bag second surface, where the first and second bag surfaces are substantially parallel to the first liquid surface;

allowing an interior of the bag to become at least partly filled with the at least one μ

org and with liquid of a second type that differs from the first type liquid;

closing the bag interior with the second type liquid contained in the bag interior;

allowing light to illuminate the at least one μ

org and to promote growth of the at least one μ

org within the bag interior for a selected time interval of at least 48 hours;

submerging the bag in the first liquid to a continuously variable, selected depth in the body of first liquid, where the bag second surface lies at a greater depth in the first liquid than does the bag first surface;

allowing at least a portion of the second liquid within the bag interior to pass through the second sequence of patches into the body of first type liquid by forward osmosis;

removing the at least one μ

org from the bag interior; and

converting at least a portion of the compounds to a selected hydrocarbon product.

2. A method for producing at least one hydrocarbon product, the method comprising:

providing a sealable bag, made of a selected bag material, having a bag interior, and being defined by a first and second opposed bag surfaces that are joined together, where the first bag surface comprises (i) a first sequence of membrane patches that permit exchange of CO₂ and O₂ across the first sequence of membrane patches and (ii) a second sequence of membrane patches that are permeable to liquid of a first type and are substantially impermeable to at least one selected micro-organism (“

μ

org”

);

positioning the bag in a body of liquid of the first type, adjacent to a surface thereof, with the bag first surface being closest to the liquid surface, between the first liquid surface and the bag second surface, where the first and second bag surfaces are substantially parallel to the first liquid surface;

allowing an interior of the bag to become at least partly filled with the at least one μ

org and with liquid of a second type that differs from the first type liquid;

closing the bag interior with the second type liquid contained in the bag interior;

allowing light to illuminate the at least one μ

org and to promote growth of the at least one μ

org within the bag interior for a selected time interval of at least 48 hours;

inverting relative positions of the bag first surface and the bag second surface relative to each other so that the bag-first surface lies at a greater depth in the first type liquid than does the bag second surface;

allowing at least a portion of the second liquid within the bag interior to pass through the second sequence of patches into the body of first type liquid by forward osmosis;

removing the at least one μ

org from the bag interior; and

converting at least a portion of the compounds to a selected hydrocarbon product.