Managing Carbon Use Efficiency in Algae Ponds for Sustainable Production

S. Twary
Los Alamos National Laboratory,
United States

Keywords: algae, carbon, biofuel

Summary:

One of the major benefits of algae production platforms for biofuels and bioproducts is the utilization of photosynthetically assimilated carbon. Ribulose bisphosphate carboxylase oxygenase (RuBisCO) is the enzyme that catalyzes assimilation of CO2 into carbon backbones for further metabolic conversion into valuable products. Maximizing RuBisCO output requires supplementing algae ponds with CO2 due to low solubility of CO2 in water and high densities of growing cells. We have developed diagnostic tools to determine saturation of RuBisCO based on carbon isotope discrimination. These tools provide valuable insight into both cultural and genetic manipulations to improve carbon use efficiency. We have designed improved carbon delivery methods based on carbonic acid systems improving carbon use significantly over CO2 gas delivery. We have identified the genetic basis for carbon concentrating mechanisms in Nannochloropsis and have genetically engineered improved lines. We have applied these methods to multiple algae species also including Chlorella. Optimizing sustainable algae production requires maximizing input utilization for product formation. CO2 dynamics can play a critical role in achieving these productivity goals.