(498g) Using environmental stress as a driving force to improve biocatalyst productivity

Adaptive laboratory evolution is a powerful tool used to develop strains for desired complex phenotypes if the phenotype-of-interest can be coupled with cell fitness or survival. However, due to the metabolic burden often associated with product formation in heterologous hosts, higher productivity does not generally lead to increased strain fitness without extensive strain engineering to force the coupling. However, for compounds with antioxidant potential, we show that by designing the appropriate environment, ALE can be successfully used to select for mutants with improved product formation. In this talk, we will show our initial proof-of-concept application and focus on subsequent molecular analyses identifying the exact beneficial mutations involved in product formation. Interestingly, most of the beneficial mutations identified cannot be rationally determined without the use of ALE, demonstrating the power of this technique in identifying genetic determinants associated with product formation. Finally, we show initial results from application of this strategy on another compound with antioxidant potential.