Genetic modification has produced algae which increase lipid production to 40% of its weight
The use of algal lipids for the production of biofuel has long been touted as an alternative to conventional fossil fuels, and to crop-based biofuels, which many are concerned can lead to land-use change and pressure on food prices. Algae can also convert a much higher percentage of their mass to oil than crops, can be grown in salt water, and require only light and carbon dioxide to produce fuel. Yet the nutrient starvation process which forces oil production can stunt growth, meaning practical yields have tended to be low.
That may be changing. In a recent paper published in Nature Biotechnology, oil and gas supermajor ExxonMobil and biotechnology research group Synthetic Genomics reported a breakthrough.
By successfully modifying strain of oil-producing algae, the team more than doubled the algae’s oil content without significantly inhibiting its growth. Using cell engineering technologies at Synthetic Genomics, the team increased the lipid (oil) content of the Nannochloropsis gaditana strain from 20% of its mass to over 40%.
This was achieved by the team’s identification of a genetic switch in the species. Lead authors Imad Ajjawi and Eric Moellering of Synthetic Genomics note that by fine-tuning this genetic sequence, the group could alter and regulate the conversion of carbon to oil. This led to a successful proof-of-concept which allowed the algae to double its lipid fraction of cellular carbon compared with its parent, while also sustaining growth.
In batch cultivation of algae, oil production is stimulated by starvation of nutrients such as nitrogen or sunlight, yet this also inhibits photosynthesis and curbs growth, leading to reduced production. The doubling of oil production in the Synthetic Genomics research is therefore a significant step forward in the technology.
Although the market for algal biofuels has cooled in recent years, advances in the technology could still bring about rapid change in biofuels usage. A recent forecast by US-based Grand View Research, for example, anticipates the market growing by 8.8% per year (CAGGGR) to reach almost US$11 billion by 2025, based on its ability to supply greater yields from smaller facilities.
The group has been collaborating on the task since 2009, but further research is still needed before this technology could be a commercial opportunity. ExxonMobil vice president for research and engineering Vijay Swarup noted: “Advancements as potentially important as this require significant time and effort, as is the case with any research and development project. 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.”
Synthetic Genomics co-founder and chairman J. Craig Venter added: “The SGI-ExxonMobil science teams have made significant advances over the last several years in efforts to optimize lipid production in algae. This important publication today is evidence of this work, and we remain convinced that synthetic biology holds crucial answers to unlocking the potential of algae as a renewable energy source.”