Stabilization of Stored Microalgae and Co-product Formation

Stage: Development
Researchers at INL have developed methods for storing concentrations of microalgae-derived biomass with much lower dry matter loss than under previously explored ensilage techniques.


Many valuable products, such as energy-dense fuels, can be synthesized from microalgae-derived biomass. However, microalgae are extremely sensitive and susceptible to degradation after harvesting. This generally creates a narrow window of opportunity to process the harvested microalgae into marketable products. This challenge is further complicated by seasonal variability in microalgae production rates due to changes in temperature, sunlight, etc. Peak microalgae production commonly occurs during summer months. Microalgae produced in the summer that is in excess of processing capacity must be stored for later use.

A number of microalgae storage options have been explored, but each presents serious problems. Drying preserves most of the biomass, but is an energy intensive option that significantly increases the cost of biofuel production. Ensilage of microalgae avoids the high energy cost of drying, but the biomass degrades under storage conditions, resulting in significantly reduced biofuel yields.

Researchers at INL have developed methods for storing concentrations of microalgae-derived biomass with much lower dry matter loss than under previously explored ensilage techniques. This method has also demonstrated production of significant volumes of bio-succinic acid and hydrogen, which would enhance the value of the stored algae and can result in secondary revenue streams for producers. This minimal dry matter loss, combined with the co-product formation, helps offset storage costs and enables economically viable, short- or long-term storage (1-6 months) of microalgae for later conversion.

INL Technology ID: BA-914

Patent Publication: https://patents.google.com/patent/US20180305656/

Article: https://www.energy.gov/eere/bioenergy/articles/age-old-farming-practice-modified-new-storage-technique-algae

Applications and Industries

Microalgae biomass production and storage;

Bio-Succinic acid production.

Benefits

Significantly less expensive than storage through drying (65% drying cost on a $/liter diesel produced basis) [2]

- Decreased microalgae loss (demonstrated 5-15% after 30 days of storage compared to typical wet storage losses of 8-37%);

- Organic acid production, particularly succinic acid, a valuable bio product and intermediate. Highest demonstrated yield was 0.34 g/g sugar in the algae;

- Useful gas production, including hydrogen;

- 4.8 to 11% increased diesel production (based on theoretical cost analyses).

Patents