Influence of a temperature shock on the synthesis efficiency of surfactants by <i>Rhodococcus pyridinivorans</i> 5Ap bacteria

Abstract

It was found that the synthesis of surfactants by R. pyridinivorans 5Ap bacteria can be increased by exposing them to a short temperature shock (55 °C for 20 minutes) after 24 hour cultivation in a minimal medium containing molasses (3 %) and hexadecane (2 %) (9 % increase in the emulsification index). Gene activation encoding global regulators of cell metabolism, including those performing a protective function under stress, was recorded in this cultivation mode. In particular, the mRNA amount determining the synthesis of the alternative transcription factor SigH increased 90.8 times and containing in the promoters its binding sites fmdB cochaperone – 59.3 times, hsp22.5 chaperone – 81.1 times, and the trxB gene encoding thioredoxin reductase – 73.1 times. In addition, it was shown that the transcriptional activation of groEL1, groEL2 and dnaJ genes determining the synthesis of heat shock proteins was 2.2, 2.6 and 4.4 times, respectively. The obtained results suggest that an increase in the alternative factor sigma H synthesis, which activates protective cellular metabolism, as well as structural, heat shock proteins under short temperature stress, leads to an increased production of surfactants, which can be used to optimize the synthesis of these secondary metabolites for biotechnological use.