Fig. 1.

Illustration of the biorefinery concept and the development time of novel bioprocesses. a In a biorefinery, plant-based feed-stocks such as sugarcane, corn, wheat, or biomass are converted into sugars that are subsequently used for microbial fermentations. In the fermentation process, cell factories convert the sugars into fuels and chemicals. b The development of cell factories is the central research and development process in connection with the development of a novel bioprocess. Construction of an efficient cell factory requires large investment, in particular in connection with bringing the cell factory from proof-of-principle stage where it is producing small amounts of the desired product to a final strain that produces the product at yields, titers, and productivities that make the process financially competitive with fossil fuel-based processes