Photobioreactor

Abstract

Provided herein is a transgenic bacteria engineered to accumulate carbohydrates, for example disaccharides. Also provided is a photobioreactor for cultivating photosynthetic microorganisms comprising a non-gelatinous, solid cultivation support suitable for providing nutrients and moisture to photosynthetic microorganisms and a physical barrier covering at least a portion of the surface of the cultivation support. Devices for the large scale and continuous cultivation of photosynthetic microorganisms incorporating photobioreactors and methods of use are disclosed. Also disclosed are methods of producing fermentable sugar from photosynthetic microorganisms using a photobioreactor of the invention.

1 . A device for cultivating photosynthetic microorganisms, comprising;
 a structure comprising a base, an axial support, and a plurality of suspension elements; the base maintaining the axial support in a substantially horizontal position; the plurality of suspension elements extending radially from and perpendicular to the axial support such that the axial support and plurality of suspension elements define a hub and spoke structure; wherein the axial support is configured to rotate with respect to the base and the plurality of suspension elements are configured to rotate around the axis defined by the axial support;   a plurality of solid, non-gelatinous cultivation supports,
 (i) each of the plurality of cultivation supports coupled to and positioned between at least two of the plurality of suspension elements, each of the plurality of cultivation supports extending substantially vertically with respect to the base and configured to maintain a substantially vertical position upon rotation of the plurality of suspension elements around the axis defined by the axial support; or 
 (ii) each of the plurality of cultivation supports coupled to and positioned between at least two of the plurality of suspension elements, such that upon rotation of each of the plurality of suspension elements around the axis defined by the axial support, each of the cultivation supports is configured to transition between substantially horizontal and substantially vertical orientations; and 
   a physical barrier disposed over at least a portion of the plurality of cultivation supports.   
     
     
         2 . The device according to  claim 1 , wherein a volume of air separates at least a portion of the barrier layer from at least a portion of the plurality of cultivation supports. 
     
     
         3 . The device according to  claim 1 , wherein the plurality of suspension elements are configured to rotate the plurality of cultivation supports around the axis defined by the axial support so as to optimize light absorbance for each of the cultivation supports. 
     
     
         4 . The device according to  claim 1 , further comprising a spray device for distributing a liquid medium over the plurality of cultivation supports. 
     
     
         5 . The device according to  claim 4 , wherein the spray device is disposed between the barrier layer and the plurality of cultivation supports. 
     
     
         6 . The device according to  claim 1 , wherein the physical barrier is disposed over at least a portion of the plurality of cultivation supports or at least a portion of the plurality of suspension elements or the structure. 
     
     
         7 . The device according to  claim 1 , wherein the physical barrier is releasably sealed so as to enclose the plurality of cultivation supports. 
     
     
         8 . The device according to  claim 1 , wherein the physical barrier, or a portion thereof, is substantially transparent to actinic irradiation. 
     
     
         9 . The device according to  claim 1 , wherein the physical barrier, or a portion thereof, is (i) substantially impermeable to solid particulate or liquid, and (ii) partially or substantially permeable to gas or vapor. 
     
     
         10 . The device according to  claim 1 , wherein the physical barrier, or a portion thereof, is a flexible physical barrier. 
     
     
         11 . The device according to  claim 1 , wherein the physical barrier comprises a first barrier portion and a second barrier portion, wherein the first barrier portion and the second barrier portion are different with respect to one or more of liquid permeability, gas permeability, or transparency to actinic radiation. 
     
     
         12 . The device according to  claim 1 , wherein each of the cultivation supports has a sheet shape, and a depth of each of the cultivation supports is substantially less than a length and a width of such cultivation support. 
     
     
         13 . The device according to  claim 1 , wherein the plurality of cultivation supports comprise a textured surface suitable for adherence of a photosynthetic microorganism. 
     
     
         14 . The device according to  claim 1 , wherein the plurality of cultivation supports comprise a non-gelatinous, textured surface suitable for culturing photosynthetic microorganisms at a density of at least about 50 grams of dry biomass per liter equivalent. 
     
     
         15 . The device according to  claim 1 , wherein the plurality of cultivation supports comprises:
 (i) a fabric comprising a natural, modified natural, or synthetic fiber, or a combination thereof;   (ii) a fabric comprising a woven fabric, a knitted fabric, a felt, a mesh of cross-linked fiber polymers, or a combination thereof;   (iii) a fabric comprising natural fibers selected from the group consisting of cotton, wool, hemp, tree fiber, other cellulosic fibers, and combinations thereof;   (iv) a fabric comprising modified natural fibers selected from the group consisting of nitrocellulose, cellulose acetate, cellulose sulfonate, crosslinked starches, and combinations thereof;   (v) a fabric comprising synthetic fibers selected from the group consisting of polyester, polyacrylate, polyamine, polyamide, polysulfone, and combinations thereof;   (vi) a material having loops;   (vii) a material having loops, the material being terry cloth; or   (viii) a combination thereof.   
     
     
         16 . The device according to  claim 1 , wherein the plurality of cultivation supports comprise: (i) a flexible material, (ii) a rigid material, or (iii) flexibly connected rigid portions, wherein the rigid portions are comprised of a rigid material. 
     
     
         17 . The device according to  claim 1 , wherein each of the plurality of cultivation supports further comprises a coating of a moisture absorbent polymer selected from the group consisting of agar, polyacrylate, polyamide, polyamine, polyethylene glycol, modified starches, and combinations thereof. 
     
     
         18 . The device according to  claim 1 , further comprising water, nutrients, or a combination thereof on or within each of the plurality of cultivation supports. 
     
     
         19 . The device according to  claim 1 , further comprising:
 at least one of a fluid supply system, nutrient supply system, gas supply system, or microorganism supply system.   
     
     
         20 . The device according to  claim 1 , wherein each of the plurality of suspension elements comprises one or more attachment points for attaching a corresponding cultivation support. 
     
     
         21 . The device according to  claim 1 , wherein each of the cultivation supports is positioned substantially horizontally between at least two of the plurality of suspension elements.