Photobioreactor

Abstract

A method of operating a closed photobioreactor for cultivation of phototrophic microorganisms. The photobioreactor comprises a culture liquid and is partially or completely surrounded by water of a water body. A density difference between the culture liquid and the surrounding water is provided so that the position of the photobioreactor in the water body is controlled. A closed photobioreactor for cultivation of phototrophic microorganisms. The photobioreactor is adapted to comprise a culture liquid and to be partially or completely surrounded by water of a water body. The photobioreactor comprises means for determining the density difference between the culture liquid and the surrounding water.

1 . A method of operating a closed photobioreactor for cultivation of phototrophic microorganisms, the photobioreactor comprising a culture liquid and the photobioreactor being partially or completely surrounded by water of a water body, wherein a density difference between the culture liquid and the surrounding water is provided so that the position of the photobioreactor in the water body is controlled. 
     
     
         2 . The method according  claim 1 , wherein the walls of said photobioreactor adapted to comprise a culture liquid comprise a water tight flexible material. 
     
     
         3 . The method according to  claims 2 , wherein said water tight flexible material is a thin film of a polymer based material. 
     
     
         4 . The method according anyone of the preceding claims, wherein the density difference is provided by provision of a salinity difference between the culture liquid and the surrounding water. 
     
     
         5 . The method according to anyone of the preceding claims, wherein the density difference is provided by provision of a temperature difference between the culture liquid and the surrounding water. 
     
     
         6 . The method according to anyone of the preceding claims, wherein the density difference is provided by increase or decrease of a gas pressure of the culture liquid. 
     
     
         7 . The method according to anyone of the preceding claims, wherein the density difference is provided so that the density of the culture liquid is increased or so that the density of the surrounding water is decreased, whereby the position of the photobioreactor in the water body is lowered. 
     
     
         8 . The method according to anyone of  claims 1  to  6 , wherein the density difference is provided so that the density of the culture liquid is decreased or so that the density of the surrounding water is increased, whereby the position of the photobioreactor in the water body is raised. 
     
     
         9 . The method according to anyone of  claims 1  to  6 , wherein the density difference is provided so that the position of the photobioreactor in the water body is maintained. 
     
     
         10 . The method according to anyone of the preceding claims, wherein the photobioreactor is equipped with one or more compartments or tubes adapted to further control the vertical position and/or shape of the photobioreactor. 
     
     
         11 . The method according to anyone of the preceding claims, wherein the photobioreactor is equipped with mechanical means adapted to further control the vertical position and/or shape of the photobioreactor. 
     
     
         12 . The method according to anyone of the preceding claims, wherein the photobioreactor has a flat panel shape. 
     
     
         13 . The method according to anyone of the preceding claims, wherein the photobioreactor comprises two or more sub-compartments adapted to comprise the culture liquid. 
     
     
         14 . The method according to  claim 13 , wherein said sub-compartments are sealed from each other. 
     
     
         15 . The method according to  claim 13 , wherein said sub-compartments are connected to allow limited liquid and/or gas transport between the subcompartments. 
     
     
         16 . The method according to anyone of the preceding claims, wherein the photobioreactor comprises means for temporarily dividing the photobioreactor into two or more sub-compartments. 
     
     
         17 . The method according to  claim 16 , wherein said means for dividing the photobioreactor into two or more sub-compartments comprises means for pressing a top sheet of the photobioreactor towards a bottom sheet of the photobioreactor such that a sub-compartment is formed inside the photobioreactor on each side of the depression. 
     
     
         18 . The method according to anyone of  claims 16 - 17 , wherein said means for dividing the photobioreactor into two or more sub-compartments comprises at least one elongated member stretched above the photobioreactor and arranged to be brought down to press a top sheet of the photobioreactor towards a bottom sheet of the photobioreactor such that a sub-compartment is formed inside the photobioreactor on each side of said at least one elongated member. 
     
     
         19 . The method according to anyone of  claims 16 - 18 , wherein said means for dividing the photobioreactor into two or more sub-compartments comprises at least one compartment arranged in contact with a top sheet of the photobioreactor and adapted to be filled with a liquid having higher density than the culture liquid, such that when the compartment is filled with the high density liquid, the filled compartment is capable of pressing said top sheet of the photobioreactor towards a bottom sheet of the photobioreactor such that a sub-compartment is formed inside the photobioreactor on each side of said filled compartment. 
     
     
         20 . A closed photobioreactor for cultivation of phototrophic microorganisms, the photobioreactor being adapted to comprise a culture liquid and the photobioreactor being adapted to be partially or completely surrounded by water of a water body, wherein the photobioreactor comprises means for determining the density difference between the culture liquid and the surrounding water. 
     
     
         21 . The photobioreactor according to  claim 20 , wherein the walls of said photobioreactor adapted to comprise a culture liquid comprise a water tight flexible material. 
     
     
         22 . The photobioreactor according to  claims 21 , wherein said water tight flexible material is a thin film of a polymer based material. 
     
     
         23 . The photobioreactor according to anyone of  claims 20 - 22 , wherein the means for determining the density difference comprises means for determining the salinity and/or the temperature of the culture liquid. 
     
     
         24 . The photobioreactor according to anyone of  claims 20 - 23 , wherein the means for determining the density difference comprises means for determining the salinity and/or the temperature of the surrounding water. 
     
     
         25 . The photobioreactor according to anyone of  claims 20  to  24 , wherein the photobioreactor is equipped with one or more compartments or tubes adapted to further control the vertical position and/or shape of the photobioreactor. 
     
     
         26 . The photobioreactor according to anyone of  claims 20  to  25 , wherein the photobioreactor is equipped with mechanical means adapted to further control the vertical position and/or shape of the photobioreactor. 
     
     
         27 . The photobioreactor according to anyone of  claims 20  to  26 , wherein the photobioreactor has a flat panel shape. 
     
     
         28 . The photobioreactor according to anyone of  claims 20  to  27 , wherein the photobioreactor comprises two or more SUb-compartments adapted to comprise the culture liquid. 
     
     
         29 . The photobioreactor according to  claim 28 , wherein said subcompartments are sealed from each other. 
     
     
         30 . The photobioreactor according to  claim 28 , wherein said sub-compartments are connected to allow limited liquid and/or gas transport between the sub-compartments. 
     
     
         31 . The photobioreactor according to anyone of  claims 20  to  30 , wherein the photobioreactor comprises means for temporarily dividing the photobioreactor into two or more sub-compartments. 
     
     
         32 . The photobioreactor according to  claim 31 , wherein said means for dividing the photobioreactor into two or more sub-compartments comprises means for pressing a top sheet of the photobioreactor towards a bottom sheet of the photobioreactor such that a sub-compartment is formed inside the photobioreactor on each side of the depression. 
     
     
         33 . The photobioreactor according to anyone of  claims 31 - 32 , wherein said means for dividing the photobioreactor into two or more sub-compartments comprises at least one elongated member stretched above the photobioreactor and arranged to be brought down to press a top sheet of the photobioreactor towards a bottom sheet of the photobioreactor such that a sub-compartment is formed inside the photobioreactor on each side of said at least one elongated member. 
     
     
         34 . The photobioreactor according to anyone of  claims 31 - 32 , wherein said means for dividing the photobioreactor into two or more sub-compartments comprises at least one compartment arranged in contact with a top sheet of the photobioreactor and adapted to be filled with a liquid having higher density than the culture liquid, such that when the compartment is filled with the high density liquid, the filled compartment is capable of pressing said top sheet of the photobioreactor towards a bottom sheet of the photobioreactor such that a sub-compartment is formed inside the photobioreactor on each side of said filled compartment.