Induced heat resistance in <i>Rhodococcus</i> strains via alkane phase translocation in aqueous-alkane 2-phase cultures

We reported previously that approximately 70% of Rhodococcus strains translocate and grow well in the alkane phase of a 2-phase aqueous-alkane culture. In addition, we recently demonstrated that Rhodococcus strains are capable of growth in alkanes and that they utilize the dissolved oxygen present in the alkane phase. In this study, we observed that some of the cells remained viable even after boiling, suggesting that cells translocated into the alkane phase exhibit increased heat resistance. To clarify this phenomenon, we assessed the heat-resistance of rhodococcal cells. Findings showed that the cells that translocated into alkanes were capable of growth on agar plates even after heat treatment. LIVE/DEAD staining confirmed that a subset of the cells survived heat treatment, whereas those grown without alkanes did not exhibit this response. These results suggest that rhodococcal cells grown in the presence of alkanes became more heat-resistant than those grown without hydrophobic liquids.