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T-00245: Engineered Cyanobacteria to Produce Essential Amino Acids While Removing Nutrients From Wastewater


Cyanobacteria represent one of the most productive life forms on the planet due to their physical robustness, efficient nutrient uptake systems, metabolic diversity and rapid growth rates. Cyanobacteria are mixotrophic and as such can grow both heterotrophically and photosynthetically.


SDSU researchers have engineered cyanobacteria to produce an artificial peptide containing only essential amino acids that are limiting in current animal feedstuffs while at the same time cleansing the wastewater of nitrogen. Producing a protein high in limiting amino acids can be used in livestock and aquaculture applications while converting the unutilized nutrients in wastewaters can convert the negative value nutrients currently in wastewaters into a high value feed component.


Typically wastewaters must be treated by physical and/or biological means to remove these nutrients, while also reducing biological oxygen demand. Current options have high associated costs and do not provide any significant economic returns from the valuable nutrients entering the process. In fact, many systems incorporate a denitrification process that converts valuable nitrogen sources into nitrogen gas that is released back into the atmosphere. At best, some systems recover energy in the form of methane, as well as nutrients that are returned to the soil, but these returns do not offset the high costs of treatment.