We would like to thank Dr. Fuzhong Zhang and members of his group at the University of Washington in St. Louis for making the time to speak to us via google hangout, a video of which is now available online. In discussion, Dr. Zhang and colleagues kindly offered insights into their recently funded project which aims to use cyanobacteria for the production of lightweight materials, based on NASA’s concept of in situ resource utilization, which is the “harnessing [of] resources at the exploration site”. Dr. Zhang talked about how cyanobacteria are ideally suited for this purpose, with their ability to use sunlight, CO2 and water to generate biomass – resources which NASA envisage to be readily available on extra-terrestrial missions.
A conventional approach might seek to produce plastics in space via metabolic engineering. However, Dr. Zhang let us in on his innovative strategy to use protein monomers for the assembly of materials, circumventing many of the challenges associated with metabolic engineering. It does however result in issues of its own, including the production of insoluble protein aggregates know as inclusion bodies. Fortunately there is a large amount of literature relating to protein production in organisms such as E. coli that can offer solutions – such as the attachment of different tags to improve solubility of protein monomers, an approach that is currently under investigation in the Zhang lab.
Eugene Kim is just starting on the biomaterials project and is excited to get going, he talked briefly about his work to establish techniques for analysis of the protein monomers – which will ultimately be vital for downstream assembly. The only other example of generating lightweight materials by this approach is the work of Chris Bowen, a third year grad student who joined us in conversation. Chris has had success in generating protein monomers in E. coli and is hoping to transfer the knowledge gained from these experiments into cyanobacteria.
Finally Dr. Zhang talked a little about the tools they are developing for manipulating cyanobacteria, which will be of interest to the wider scientific community and could help establish Synechocystis sp. PCC 6803 as a phototrophic chassis for synthetic biology. Although there is a history of transforming cyanos by homologous recombination, a characteristic of these organisms is that each cell contains many copies of the genome. Resultantly the generation of stable transformants requires the process of several rounds of selection until all copies of the genome contain the desired modification, otherwise transgenes and mutations tend to be lost. To reduce the time necessary for selection of mutants the Zhang lab are using the genome editing tools such as CRISPR-Cas (a version of which is found in cyanobacteria), a technique that also has the advantage of being able to target multiple locations in the genome simultaneously.
NASA are also funding other projects to look into how the growth and functioning of microorganisms is effected by zero gravity, and the engineering aspects of the project are being considered elsewhere. Dr. Zhang’s project is at the stage of fundamental research – so unfortunately no experiments will be carried out in space! However, the ability to produce materials from sustainable resources could have many applications here on earth, and the tools being developed will help push forward cyanobacterial research.
Dr. Zhang’s group is also hiring at the moment to work on the biomaterials project, so if you are interested please contact him at firstname.lastname@example.org.