Team:Amsterdam/Description
Project Description
In brief
Very recently, there’s been a small shift in the world of synthetic biology. Rather than focus on single organisms - the modus operandi of the biotech industry - researchers are starting to recognize that synthetic ecosystems, consortia of multiple bacterial species, can be used for higher yields, robustness and more diverse purposes. Our goal is to tap into this potential by creating a self-sustaining bio-factory of cyanobacteria - little fellows that need only CO2 and light - and product-producing E. coli, the general workhorse of the synthetic biology world.
In short: the cyanobacteria will create sugars from CO2 and sunlight, which it will release and feed to E. coli as a result of our applied synthetic genetic circuits. E. coli will then be engineered to use these sugars to create a product. In our proof-of-concept bio-factory, this product will be fuel. This platform, however, can be expanded to produce any product E. coli can fabricate - medicine, plastics, commodity chemicals - as long as it is fueled by the cyanobacteria that only needs light and CO2.
Background
Fossil fuels have powered the development of our society since the industrial revolution. As a consequence, two main issues have risen. Firstly, the atmospheric CO2 concentration has substantially increased due to the consumption of fossil fuels, leading to harmful changes in the planet ecosystem (Hughes, 2000). Secondly, non-renewable resources such as gas, coal and crude oil, will become depleted at some point in the coming future (Shafiee et. al, 2009). To face this global problem many engineers and scientists have focused on finding renewable energy sources. However, the production of green energy has faced considerable limitations and drawbacks over the past decades.
Over the past 30 years, the only two biofuels produced at industrial scales have been biodiesel and bioethanol (Antoni et al., 2007). Biodiesels are fatty acids derived from biological long chain oils (Knothe, 2006). The classic approach in the production of these biofuels has been the alkaline catalysis of plant-derived oils. New methods, such as production via fermentation (Steen et al., 2010), or enzymatic reactors (Poppe et al., 2014), have been developed. Bioethanol is mainly produced by microbial fermentation, either by yeast or prokaryotic organisms, using plant derived materials (starch or glucose syrups) as a substrate for fermentation.
Biofuels hold clear advantages over fossil fuels in terms of reduction of greenhouse gases emissions and fostering energetic independence. On the other hand, the use of food crops as a substrate in both processes, fosters the devotion of agricultural lands towards energy production - interfering with the food market and increasing prices of basic products (Pimentel et al., 2008). In addition, such processes do not exploit the whole plant thus efficiency of transforming sunlight and CO2 into biofuels is low.
To overcome these problems, systems and synthetic biology methods have been applied to incorporate non-native enzymatic activities into photosynthetic microorganisms to directly produce biofuels. Cyanobacteria has a fast cell growth and low nutrient requirements making it a very suitable target for industrial scale biofuel production. Although promising, cyanobacterial powered production of biofuel has some unsolved issues, such as the toxicity of the medium and the low yields (Jin et al., 2014).