Compositions and methods for continuous harvesting of suspension growth cultures

Abstract

Embodiments herein concern compositions, methods and uses for harvesting suspension cultures or decontaminating waters. In certain embodiments, suspension microorganism cultures can comprise algal cultures. In some embodiments, harvesting suspension cultures may include using a composition capable of interacting with the culture in order to separate the culture from a liquid or media.

1 . A method for harvesting a suspension of an organism in a liquid, comprising:
 adding a magnesium agent to the suspension to produce a flocculant comprising the organism and the magnesium agent;   separating the flocculant from the liquid; and   harvesting the organism.   
     
     
         2 . The method of  claim 1 , wherein the flocculant is produced at a pH about 9.0 to pH about 11.5. 
     
     
         3 . The method of  claim 1 , wherein the magnesium agent is a positively-charged agent comprising a magnesium hydroxide. 
     
     
         4 . The method of  claim 1 , wherein the separating step comprises adding a negatively charged magnetic particle and exposing the flocculant to a magnetic field. 
     
     
         5 . The method of  claim 1 , wherein harvesting the organism occurs after the flocculant is exposed to a reduced pH of about 6.0 to about 7.5. 
     
     
         6 . The method of  claim 1 , further comprising:
 adding a negatively charged non-magnetic material to the suspension to produce a complex comprising the flocculant and the negatively charged non-magnetic material; and   allowing the complex to settle out of the suspension.   
     
     
         7 . The method of  claim 6 , wherein the negatively charged non-magnetic material is selected from silica, tungsten, aluminum, aluminum hydroxides, copper, allay, rare earth materials, ceramic materials, clay, glass, calcium, and carbon, organic materials and composite materials. 
     
     
         8 . The method of  claim 6 , wherein the negatively charged non-magnetic material has a particle size of 0.5 μm to 10 μm. 
     
     
         9 . The method of  claim 6 , further comprising harvesting the non-magnetic material for reuse. 
     
     
         10 . The method of  claim 1 , wherein the organism is an algae. 
     
     
         11 . The method of  claim 10 , wherein the algae is further harvested for an algal yield. 
     
     
         12 . The method of  claim 11 , wherein the algae is further harvested for biofuel extraction. 
     
     
         13 . A method for decontaminating water comprising a particulate or contaminant, the method comprising:
 adding a positively charged magnesium agent to the water to form a flocculant comprising the positively charged magnesium agent and the particulate or contaminant;   adding a non-magnetic material to the contaminated water to produce a complex comprising the particulate or contaminant and the flocculant;   allowing the complex to settle out of the water;   separating the complex from the water to produce decontaminated water; and   reusing the decontaminated water.   
     
     
         14 . The method of  claim 13 , wherein the decontaminated water can be used for non-potable or potable use. 
     
     
         15 . A method for separating a negatively charged particulate from a liquid having a high concentration of magnesium ions, the method comprising:
 increasing the pH of the liquid to a pH of at least 8.5 to about 12.5 to produce a first complex comprising the particulate and a magnesium precipitate;   adding a negatively charged inorganic particle to the liquid to form second complex comprising the first complex and the negatively charged inorganic particle; and   separating the second complex from the liquid.   
     
     
         16 . The method of  claim 15 , further comprising exposing the second complex to a is exposed to a pH of about 6.0 to about 7.5 to recover the negatively charged inorganic particle. 
     
     
         17 . The method of  claim 15 , wherein the negatively charged particulate is algae. 
     
     
         18 . The method of  claim 15 , wherein the liquid contains from about 600 mg/L to about 2000 mg/L of magnesium in the form of an inorganic salt. 
     
     
         19 . The method of  claim 15 , wherein the negatively charged inorganic particle has a density of from about 2.6 g/cm 3  to about 19.3 g/cm 3 . 
     
     
         20 . The method of  claim 15 , wherein the negatively charged particle has a particle size of from about 1 μm to about 100 μm.