Fig. 2

a Kinetics of the separation of olefin-producing and non-producing M. luteus cells in mixtures of two strains, measured by estimating the frequency of an associated kanamycin resistance marker. The 10-ml mixes contained 2 strains grown to the stationary phase in complex medium (48 h of growth in LB). Samples from the upper phase were collected (0.1 ml) at the indicated time points and dilutions were plated on LB plates with and without kanamycin. The LB kanamycin/LB ratio represents the relative abundance of the kanamycin resistant cells in the mix. The box plots show the data from 4 replicates (n = 4). b Total olefin content, determined by GC–MS, in fractions of Mix A (consisting of M. luteus ope and M. luteus ΔoleABCD:kan) after separation by sedimentation for 4 h. The cultures of the two strains were grown separately for 48 h in rich medium and 250 ml of each were mixed in a 1:1 ratio. The fractions (40 ml each) were normalized by cell density and subjected to 4 separate extractions with hexane. Each hexane extract was analyzed by GC–MS and the total olefins were quantified using an internal standard (triacontane). The boxplots represent the quantification data from four extractions (n = 4)