Unprecedented biomass and fatty acid production by the newly discovered cyanobacterium Synechococcus sp. PCC 11901

Abstract

Cyanobacteria, which use solar energy to convert carbon dioxide into biomass, are potential solar biorefineries for the sustainable production of chemicals and biofuels. However, yields obtained with current strains are still uncompetitive compared to existing heterotrophic production systems. Here we report the discovery and characterization of a new cyanobacterial strain, Synechococcus sp. PCC 11901, with potential for green biotechnology. It is transformable, has a short doubling time of {approx}2 hours, grows at high light intensities and a wide range of salinities and accumulates up to 18.3 g dry cell weight/L of biomass - 2-3 times more than previously described for cyanobacteria - when grown in a modified medium containing elevated nitrate, phosphate and iron. As a proof of principle, PCC 11901 engineered to produce free fatty acids did so at unprecedented levels for cyanobacteria, with final yields reaching over 6 mM (1.5 g/L), comparable to those achieved by heterotrophic organisms.