Adaptive Laboratory Evolution for Enhanced Tyrosol Tolerance Enables High-Titer Salidroside Production in <i>Escherichia coli</i>

mutation finely modulates the AcrAB efflux pump to control intracellular tyrosol availability. Importantly, this synergy establishes a precursor retention mechanism, maintaining high intracellular substrate concentrations necessary for efficient downstream glycosylation without compromising cell viability. This work establishes a robust and scalable platform for phenolic glycoside production and highlights the critical importance of precursor retention mechanisms in resolving the tolerance-yield trade-off when engineering microbial cell factories for toxic intermediates.