The need to improve conversion efficiency in biofuel production.
The energy stored in biofuel is derived from biomass, which, in turn, is derived from photosynthesis of solar energy. Efficiency for converting solar energy to biomass conversion for plants is at most 2% (e.g., Miscanthus). The subsequent conversion from biomass to biofuel is 50% efficient. A simple calculation would indicate that US would require 4-5% of US land area or 20-30% of US cropland for producing biomass for biofuel in order to meet the fuel demand. Thus, biofuel, in principle, as a renewable energy source, is a sustainable strategy, but there is a clear need to maximize the conversion efficiency. Synthetic biology enables re-design of organisms and processes to shorten and to expedite the pathway from sunlight to fuel.
What is synthetic biology?
According to syntheticbiology.org, synthetic biology refers to the design and fabrication of biological components and systems that may or may not already exist in the natural world. It takes parts of natural biological systems, characterizing and simplifying them, and using them as a component of a highly unnatural, engineered, biological system. For instance, Voigt and colleagues (2005) engineered Salmonella typhimurium, which normally secrete infectious proteins, to secrete spider silk proteins, a strong elastic biomaterial, instead.
Different approaches in producing syntheticbiofuels
One of the major players in the new emerging market of synthetic biofuel is Amyris Biotechnologyies (Emeryville, California). The company, founded by Jay Keasling at UC Berkeley, recognized as the world leader in the field of synthetic biology, is working on new type of biofuel derived from microbial fermentations. It adapts tools from molecular biology and genetics to insert new biological pathways into microorganisms to produce hydrocarbon-based fuels. Amyris claimed to engineer several fuels that are better than ethanol or conventional biodiesels, in terms of energy-storage, performance advantages, compatibility with existing engines, low net emissions, and cost of production.
Amyris is well-backed by the energy industry. Their CEO was the head of BP fuel operation in US. BP recently funded a $ 250million research initiative at UC Berkeley to find better ways of producing biofuels, where Amyris will be the center piece of the initiative. Recently, Amyris announced a partnership with Crystalsev, one of Brazil’s largest ethanol distributors and marketers, to commercialize advanced fuels diesel, jet fuel and gasoline derived from sugar cane.
LS9 (San Carlos, CA), another Bay area startup, takes another approach to produce fuel from synthetic biology. LS9 inserts gene pathways that other microbes, plants, and animals use to store energy into microbes. The company focuses on production of fatty acid, and develop technologies to “clip” oxygen atoms out of the fatty acids to make biocrude (pure hydrocarbons). Rather producing standard biofuels (like ethanol or biodiesel), LS9 wants to use synthetic biology to produce specific types of molecules that can be made into high performance fuels.
Other emerging companies competing in production of synthetic biofuels include, (i) Codexis, which is investigating the possibility of making enzymes to create octanol and (ii) Synthetic Genomics (Rockville, MD), founded by Craig Venter, who cracked the human genome.
So when do we expect synthetic biofuel on the market? According to Amyris CEO Melo, they hope, “To make a Jet-A equivalent with better properties on energy and freezing point with a $40 barrel cost equivalent by 2010 or 2011”. Obviously, there will be many challenges, but it seems synthetic biofuel may hold the key to solve our energy crisis.
