FIG. 3.

Continuous two-liquid-phase culture with P. putida SMA. (A) Genotype of P. putida SMA. The mini-transposon of pJMS-SMA (determined by the I and O ends [black boxes]) contained the alk expression cassette for the synthesis of xylene oxygenase, the selection marker npt for kanamycin resistance, and xylE for easy colorimetric selection. The selection marker is flanked by res sites (grey boxes), which are the substrate of the RP4 resolvase. Arrows indicate promoters (P). T4t, phage T4 transcriptional terminator. (B) Continuous culture (D = 0.2 h⁻¹) of P. putida SMA on mineral medium with 0.5% (wt/vol) citrate as the carbon source. The arrow indicates the start of the organic feed of a mixture of long-chain alkanes containing 1% octane and 1% styrene, which accounted after equilibration of the system for 10% of total liquid volume. l_tot, liter of total liquid volume; l_aq, liter of the aqueous phase.