Researchers have genetically engineered microbes to process brown seaweed into biofuel. The work by researchers including Dr Yasuo Yoshikuni from Bio-Architecture Lab - BAL - have partnered with DuPont, the US Department of Energy’s ARPA-E labs, and Norway’s Statoil to develop a chemistry that would unlock the energy in seaweed, creating a fuel that’s cheaper than any alternatives produced to date. In this vision of the not-so-distant future, BAL foresee large underwater farms as a source of renewable energy.
BAL has built three seaweed farms on the Pacific coast of Chile. The BAL researchers have focused on brown seaweed because of its high sugar content, which provides a good biomass. What makes brown seaweed a super green energy source? Brown seaweed doesn’t compete with food crops for land or fresh water, making it an übergrün energy source. Yoshikuni says “the seaweed uses a different type of carbohydrate called an alginate which cannot be broken down by the land based E. coli – Escherichia coli - bacteria normally used in industry”.
“This bottleneck means biofuel from seaweed is too expensive to compete with regular petroleum-based fuels,” Dr Yoshikuni said.
To overcome the problem, Dr Yoshikuni and his colleagues examined a marine microbe called Vibrio splendidus, which naturally metabolises and consumes seaweed in the ocean. ”We don’t know if we can scale up these microbes so we genetically engineered terrestrial E. coli microbes instead,” Dr Yoshikuni said.
BAL’s patented technology converts seaweed carbohydrates into renewable chemicals and fuels. BAL technology works by first transforming seaweed into a renewable chemical intermediate, and from this intermediate, chemicals and fuels are produced through chemical synthesis or fermentation.
Reporting in the journal Science, Dr Yoshikuni and his colleagues successfully isolated a 36,000 base pair DNA fragment from V. splendidus which encodes enzymes that metabolise alginate.
“Using synthetic biology and enzyme engineering, the DNA strand was spliced into the E. coli bacteria, which was then able to digest the sugar polymers in the seaweed converting them into ethanol,” Dr Yoshikuni said.
BAL has developed a diverse product portfolio that provides large market opportunities at varying price points. Products include road transport fuels, green plastics, surfactants, agrochemicals, synthetic fibers and nutraceuticals. The key benefits of the BAL technology are:
- A Single Platform. BAL converts seaweed carbohydrates into one renewable chemical intermediate that is affordable and scalable for both fuels and chemicals.
- Commercial Focus. Leveraging the single platform, BAL will first commercialize high-value products to generate early cash flow that simultaneously paves the path for larger market opportunities.
- First Mover Advantage. With over 60 patents or patents pending, BAL has carved a broad IP estate for the use of seaweed as a biomass for chemicals and fuels.
The researchers say if this process can be successfully scaled-up, seaweed could help meet the growing demand for sustainable fuel.
According to Dr Yoshikuni, there are already commercial processes for aqua farming of seaweed especially in Asia with 15 million tonnes produced annually.
“Using 3 per cent of the world’s coastlines we can replace 5 per cent of total oil consumption. That’s 60 billion gallons of fuel,” Dr Yoshikuni said.
He says it would be grown on long, submerged ropes. ”We seed the juvenile seaweed onto long ropes which are dangled into the sea and the seaweed grows on these ropes getting all its nutrients from the sea and sun,” Dr Yoshikuni said. ”The harvested seaweed would be fed to the genetically engineered E. coli, with the ethanol refined in a similar way to existing processes. We are currently looking into the environmental impact of the project on a commercial scale.”
Dr Yoshikuni says seaweed also absorbs industrial waste such as phosphorus and nitrogen, which can help reduce the incidence of algal blooms. ”We believe seaweed is green energy and can become the most sustainable and upscaleable biomass for the next generation,” he said.
Dr. Yoshikuni co-founded Bio Architecture Lab and has developed the first platform technology of synthetic biology that enables the conversion of a previously untapped feedstock (seaweed) into a variety of chemicals. He currently directs BAL’s core research programs and Intellectual Property efforts. Dr. Yoshikuni brings a decade of research experiences in protein engineering, computational enzyme design, and metabolic engineering into BAL. He has authored numerous publications including Nature and Chemistry & Biology. Dr. Yoshikuni completed his Ph.D. at University of California, Berkeley with Professor Jay D. Keasling. He then pursued a post-doctorate as a Howard Hughes Medical Institute and Jane Coffin Child’s memorial fellow at University of Washington, Seattle with Professor David Baker.