SOXRS GENE INCREASED THE LEVEL OF ORGANIC-SOLVENT TOLERANCE IN ESCHERICHIA-COLI

Escherichia coli strain JA300 grows in the presence of n-hexane, but n ot in the presence of cyclohexane. We isolated a 10.5-kb DNA fragment that provided cyclohexane tolerance on a multi-copy plasmid, from the chromosomal DNA of JA300. In this fragment, there were found C-termina l 10-amino acids truncated soxR (soxR') and soxS which control the sup eroxide response regulon genes. Characterization of subclones found th at both the soxR' and overexpression of the soxS increased the levels of organic solvent tolerance in several E. coli strains.