Adaptive laboratory evolutions used in this study.

GR, average stable growth rate for each condition, the endpoint culture and previous two recorded growth rates from each parallel evolution were considered in the average; N/A, not available; No. of mutations were determined by whole genome-sequencing; Generations, averaged cumulative number of generations of individual populations required for a stable phenotype to be reached; CCD, averaged cumulative number of cell divisions of individual evolved populations required for a stable phenotype to be achieved. The standard deviation of GRs for glycerol- and l-lactate-evolved populations with NTG was less than 1% of the mean values.