Directed evolution of biofuel-responsive biosensors for automated optimization of branched-chain alcohol biosynthesis.

The biosynthesis of short-chain alcohols is a carbon-neutral alternative to petroleum-derived production, but strain screening operations are encumbered by laborious analytics. Here, we built, characterized and applied whole cell biosensors by directed evolution of the transcription factor AlkS for screening microbial strain libraries producing industrially relevant alcohols. A selected AlkS variant was applied for in situ product detection in two screening applications concerning key steps in alcohol production.

Biotin-independent strains of Escherichia coli for enhanced streptavidin production.

Biotin is an archetypal vitamin used as cofactor for carboxylation reactions found in all forms of life. However, biotin biosynthesis is an elaborate multi-enzymatic process and metabolically costly. Moreover, many industrially relevant organisms are incapable of biotin synthesis resulting in the requirement to supplement defined media.