Photoautotrophic
ethanol production using model cyanobacteria is an attractive technology that
offers potential for sustainable ethanol production as a biofuel. Model strains
of Synechocystis PCC6803 have been
metabolically engineered to convert central metabolic intermediates such as
pyruvate to acetaldehyde via cloned heterologous pyruvate decarboxylase and
from acetaldehyde to ethanol via cloned homologous or heterologous alcohol
dehydrogenase. While the technology is now proven, strategies are required to
increase the ethanol levels through metabolic and genetic engineering and in addition,
production and process strategies are required to make the process sustainable.
Here we discuss both genetic and molecular strategies in combination with
downstream strategies that are being applied while also discussing challenges
to future application.