Eight years after agreeing to fund research to develop next-generation biofuels from photosynthetic algae, ExxonMobil Corp. said Monday it reached a breakthrough with partner Synthetic Genomics Inc. that more than doubled the oil content from an algae strain without significantly inhibiting its growth.
Using advanced cell engineering technologies at Synthetic Genomics based in La Jolla, CA, the joint research team modified an algae strain to enhance oil content from 20% to more than 40%. Results were published in the peer-reviewed Nature Biotechnology by lead authors Imad Ajjawi and Eric Moellering of Synthetic Genomics.
The breakthrough holds potential for next-generation fuels for transportation, and as a feedstock for the petrochemical industry.
"This key milestone in our advanced biofuels program confirms our belief that algae can be incredibly productive as a renewable energy source with a corresponding positive contribution to our environment," said ExxonMobil's Vijay Swarup, vice president for research and development at the oil major's Research and Engineering Co. "Our work with Synthetic Genomics continues to be an important part of our broader research into lower-emission technologies to reduce the risk of climate change."
Using a proof-of-concept approach, the new process to increase oil production identified a genetic switch that could be fine-tuned to regulate converting carbon to oil in the algae species Nannochloropsis gaditana.
Major inputs for phototropic algae production "are sunlight and carbon dioxide, two resources that are abundant, sustainable and free," said Synthetic Genomics CEO Oliver Fetzer. "Discoveries made through our partnership with ExxonMobil demonstrate how advanced cell engineering capabilities at Synthetic Genomics can unlock biology to optimize how we use these resources and create solutions for many of today’s sustainability challenges -- from renewable energy to nutrition and human health."
Algae long has been regarded as a potential sustainable fuel option, but researchers were hindered in developing a strain high in oil content and able to grow quickly, two critical characteristics for scalable and cost-efficient oil production. Slower growth has been an adverse effect of previous attempts to increase algae oil production volume.
A key objective of the ExxonMobil-Synthetic Genomics collaboration has been to increase the lipid content of algae while decreasing the starch and protein components without inhibiting the algae's growth. Limiting availability of nutrients such as nitrogen is one way to increase oil production in algae, but it also may inhibit or even stop photosynthesis, stunting algae growth and ultimately the volume of oil produced.
Oil from algae can also potentially be processed in conventional refineries, producing fuels no different from convenient, energy-dense diesel. Oil produced from algae also holds promise as a potential feedstock for chemical manufacturing.
"Advancements as potentially important as this require significant time and effort, as is the case with any research and development project," Swarup said. "Each phase of our algae research, or any other similar project in the area of advanced biofuels, requires testing and analysis to confirm that we're proceeding down a path toward scale and commercial viability."
ExxonMobil also is researching other emission-reducing technologies, including carbon capture and sequestration. Last year the oil major partnered with Connecticut-based FuelCell Energy Inc. to advance the use of carbonate fuel cells to economically capture carbon emissions from power plants while generating hydrogen and additional electricity. Since 2000, ExxonMobil has spent about $8 billion to develop and deploy lower-emission energy solutions across its operations.