CRISPR-Cas9 for the genome engineering of cyanobacteria and succinate production (Li et al, 2016).
Cyanobacteria
Cyanobacteria are photosynthetic prokaryotes that capture sunlight for energy using chlorophyll a and various accessory pigments. They are common in lakes, ponds, springs, wetlands, streams, and rivers, and they play a major role in the nitrogen, carbon, and oxygen dynamics of many aquatic environments. Modern-day cyanobacteria include some 2000 species in 150 genera and 5 orders, with a great variety of shapes and sizes, Table 1 (Vincent, 2009).
Table 1. The five orders of cyanobacteria recognized in the classic botanical taxonomic scheme Order.
(Vincent, 2009)
The need for a sustainable energy source has never been greater, as demands for energy increase worldwide and current oil reserves face depletion (Young, 2014).
Figure 1. Cyanobacteria in inland water ecosystems. Top left: Photomicrograph of Microcystis aeruginosa from a eutrophic lake. The bright areas inside each cell are due to the scattering of light by the gas vacuoles. Top right: Photomicrograph of Nostoc from a high Arctic lake. The larger, more spherical cells are heterocysts, the sites of nitrogen fixation. Bottom right: A carotenoid-rich cyanobacterial mat in a pond on the McMurdo Ice Shelf, Antarctica. Bottom left: Cyanobacterial mats in a geothermal spring, New Zealand. (Vincent, 2009).
Cyanobacteria have a fast doubling time, are easily manipulated genetically, use sunlight as an energy source, and recycle CO2, making them an advantageous platform for the production of biofuels. A cyanobacteria that has been extensively used in the research of cyanobacterial biofuel production is Syenchococcus (Young, 2014).