Sustainable production of high-value compounds using cyanobacteria

Since my Undergraduate degree in Biological Sciences, I have been especially interested in applying my studies to global sustainability challenges.

During my degree I found modules on biotechnology and bioengineering the most engaging, for example the CRISPR/Cas9 system which is now used so readily in the lab for genome editing. I am therefore highly interested in working on manipulating natural systems or cellular functions for further purposes.

I have since studied an MSc in Biotechnology and Microbiology which concentrated on using molecular biology techniques to tackle issues of sustainability.

For my MSc project I chose to join a biochemistry team looking at the unique photosynthetic capabilities of the purple bacteria Blastochloris viridis.

The light harvesting complex, containing a unique carotenoid, allows this bacteria to use the far red portion of the solar spectrum to photosynthesise, thus completing the lowest energy photosynthesis.

This project allowed me to explore the use of molecular biology to pursue questions surrounding sustainability and food security and I found great inspiration from the application of biological research to current global problems.

Identifying new cyanobacterial strains that could be suitable for compound production would require proof of good growth rate, especially as many cyanobacterial strains lag behind heterotrophic organisms.

They would also have to grow well in a range of conditions, be transformable for genetic manipulation and prove to produce valuable compounds of choice at a level comparable to or better than currently used strains.

Further downstream, newly identified cyanobacteria strains, for example that recently characterised by Wlodarczyk et al. 2020, need to be deemed suitable for scale up.

This could involve determining growth rates of different strains in photobioreactors I would have access to, investigating the recovery of desired compounds and optimisation of the entire process. In parallel, looking at the challenges of genome editing cyanobacteria would be a worthwhile and interesting project.

As many cyanobacteria are polyploidy, ensuring successful editing of all chromosome copies adds a specific extra challenge.

Similarly, the low availability of resistance markers adds difficulty and generating markerless strains for dual or triple genetically altered strains is extra challenging as clones need to be screened after each transformation (Hitchcock et al. 2020).

Thinking of potential avenues for genetic manipulation of cyanobacteria strains for example the recent advances with use of CRISPR/Cas9 would be interesting.