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Genetically Modified Microalgae and Their Use as Biosorbents

Stage: Development

The removal of contaminants from industrial wastewater, groundwater, and soil is becoming increasingly important; however, selectively removing trace concentrations of specific substances from water streams is often technically challenging, energy intensive, and/or uneconomical. Market-parity remediation and mitigation of water-stream contaminants require low-cost and scalable technologies as alternative methods of element and compound extraction. Researchers at NREL have developed photosynthetic microorganisms, such as diatoms and algae, to uptake specific elements or compounds and sequester them. NREL’s microorganisms can improve contaminant removal at very low concentrations, can reduce operating and capital costs of contaminant sequestration, and are easy to scale in diverse environmental conditions.



NREL’s microorganisms are modified to express exogenous binding peptides to target specific contaminants like heavy metals for sequestration and removal. In particular, researchers at NREL have demonstrated targeted contaminant removal with diatoms including exogenous binding peptides. Using these peptides, these genetically engineered living diatoms absorb/adsorb specific elements or compounds and sequester them within their inorganic frustule structures or immobilize them on frustule surfaces. Once biosorption is completed, the dispersed diatoms can be removed from a water stream, using simple physical or chemical techniques. Alternatively, diatoms may be positioned on a scaffold so that they are spatially fixed. A scaffold may be constructed of a bioderived material capable of immobilizing diatoms within the scaffold’s matrix. In the latter case, contaminants may be separated from a water stream by removal of the macroscopic composite material containing entrapped diatoms with sequestered contaminants.

To learn more about Genetically Modified Microalgae and Their Use as Biosorbents, please contact Eric Payne at:
Eric.Payne@nrel.gov
ROI-19-27.

Applications and Industries

NREL’s genetically engineered photosynthetic microorganisms can provide

  • Treatment of fresh water, sea water, brine, industrial wastewater effluent streams, municipal wastewater streams, agricultural wastewater streams, and/or mining tailings;
  • Recovery of elements and/or compounds from dissolved ash waste streams produced when trash/refuse is incinerated;
  • Removal of undesirable waste elements, like lead, selenium, cadmium, copper, nickel, chromium, and/or mercury, from a stream being treated; and
  • Recovery of desirable elements, like rare earth elements and noble metals, from a stream being treated.

Benefits

In general, NREL’s genetically engineered photosynthetic microorganisms

  • Are inexpensive,
  • Can be grown in large quantities,
  • Can survive in a variety of environmental conditions including salt and fresh water, and
  • Require only the inputs of light and carbon dioxide to survive and reproduce.

In particular, NREL’s systems and technologies based on genetically modified diatoms

  • Require minimal nutrient and energy input,
  • Produce their own peptides or proteins for metal binding, so these peptides (or other chemical/material alternatives) do not need to be synthesized artificially,
  • Remove low concentrations of metals or other chemicals from water, and
  • Can contain immobilized diatoms within scaffolds of bioderived materials, which enable membrane-filtration applications.