Combinatorial Use of Environmental Stresses and Genetic Engineering to Increase Ethanol Titres in Cyanobacteria

Fraser Andrews, Matthew Faulkner, Helen Toogood, Nigel Scrutton

Research output: Contribution to journalArticlepeer-review


Current industrial bioethanol production by yeast through fermentation generates carbon dioxide. Carbon neutral bioethanol production by cyanobacteria uses biological fixation (photosynthesis) of carbon dioxide or other waste inorganic carbon sources, whilst being sustainable and renewable. The first ethanologenic cyanobacterial process was developed over two decades ago using Synechococcus elongatus PCC 7942, by incorporating the recombinant pdc and adh genes from Zymomonas mobilis. Further engineering has increased bioethanol titres 24-fold, yet current levels are far below what is required for industrial application. At the heart of the problem is that the rate of carbon fixation cannot be drastically accelerated and carbon partitioning towards bioethanol production impacts on cell fitness. Key progress has been achieved by increasing the precursor pyruvate levels intracellularly, such as upregulating synthetic genes and knocking out pathways competing for pyruvate. Studies have shown that cyanobacteria accumulate high proportions of carbon reserves that are mobilised under specific environmental stresses or through pathway engineering to increase ethanol production. When used in conjunction with specific genetic knockouts they supply significantly more carbon for ethanol production. This review will discuss the progress in generating ethanologenic cyanobacteria through chassis engineering, and exploring the impact of environmental stresses on increasing carbon flux towards ethanol production.
Original languageEnglish
JournalBiotechnology for Biofuels
Publication statusAccepted/In press - 5 Dec 2021

Research Beacons, Institutes and Platforms

  • Manchester Institute of Biotechnology


Dive into the research topics of 'Combinatorial Use of Environmental Stresses and Genetic Engineering to Increase Ethanol Titres in Cyanobacteria'. Together they form a unique fingerprint.

Cite this