Methods of increasing biomass productivity in algae cultures

Abstract

The present disclosure relates to methods of culturing algae that overcomes catabolic repression of photosynthesis in mixotrophic growth.

We claim: 
     
         1 . A method for large-scale cultivation of algae, the method comprising:
 cultivating algae in a cultivation apparatus;   providing light to the cultivation apparatus;   not providing supplemental O 2  to the cultivation apparatus.   
     
     
         2 . The method of  claim 1 , further comprising administering a feedstock comprising a mixotrophic substrate to the cultivation apparatus. 
     
     
         3 . The method of  claim 1 , further comprising not providing supplemental CO 2  to the cultivation apparatus. 
     
     
         4 . The method of  claim 2 , wherein the stoichiometric oxygen supply in the cultivation apparatus is less than the stoichiometric carbon concentration introduced into the cultivation apparatus by the mixotrophic substrate in the feedstock as defined by the equation CO 2 +H 2 O+PAR CH 2 O+O 2 . 
     
     
         5 . The method of  claim 2 , wherein the cultivation apparatus is an open culture system, the cultivation apparatus is a tubular photobioreactor, and the mixotrophic substrate comprises wastewater. 
     
     
         6 . The method of  claim 2 , wherein the cultivation apparatus is a closed culture system. 
     
     
         7 . The method of  claim 6 , further comprising not providing supplemental CO 2  to the cultivation apparatus. 
     
     
         8 . The method of  claim 7 , wherein the mixotrophic substrate comprises wastewater and feedstock is introduced to the cultivation apparatus when the cultivation apparatus is exposed to light intensity sufficient to support photosynthesis. 
     
     
         9 . The method of  claim 8 , wherein the intensity of light sufficient to support photosynthesis is greater than 50 μmol photosynthetically active radiation per square meter per second. 
     
     
         10 . The method of  claim 6 , wherein the mixotrophic substrate comprises wastewater and feedstock is introduced to the cultivation apparatus when the cultivation apparatus is exposed to light intensity sufficient to support photosynthesis. 
     
     
         11 . The method of  claim 10 , wherein the intensity of light sufficient to support photosynthesis is greater than 50 μmol photosynthetically active radiation per square meter per second. 
     
     
         12 . The method of  claim 10 , further comprising not providing supplemental CO 2  to the cultivation apparatus. 
     
     
         13 . The method of  claim 6 , wherein the algae cultivated in the cultivation apparatus comprises Cyanidiophyceae. 
     
     
         14 . The method of  claim 13 , wherein the mixotrophic substrate comprises wastewater and feedstock is introduced to the cultivation apparatus when the cultivation apparatus is exposed to light intensity sufficient to support photosynthesis. 
     
     
         15 . The method of  claim 14 , wherein the intensity of light sufficient to support photosynthesis is greater than 50 μmol photosynthetically active radiation per square meter per second. 
     
     
         16 . The method of  claim 6 , wherein the cultivation apparatus is a tubular photobioreactor. 
     
     
         17 . The method of  claim 2 , wherein the feedstock provides an excess amount of mixotrophic substrate relative to the cultivation time period for the algae culture or algae in the cultivation apparatus. 
     
     
         18 . The method of  claim 1 , wherein the algae is mixotrophic. 
     
     
         19 . The method of  claim 1 , wherein the algae is thermophilic, acidophilic, or both. 
     
     
         20 . The method of  claim 1 , wherein the algae is red algae, green algae, or  cyanobacteria.    
     
     
         21 . The method of  claim 1 , further comprising mechanically mixing the algae culture or mechanically mixing the algae in the cultivation apparatus.