Fig. 1.

a Screening of solvent tolerance σ⁷⁰ mutants C1–C9 at 38 % cyclohexane; b cyclohexane tolerance of E. coli JM109 harboring σ⁷⁰ mutants C9 and WT; c cell growth of E. coli JM109 harboring C9 mutant and WT in absence of organic solvent. Strains were cultured at 37°C. For a and b, different concentration of cyclohexane was added when OD₆₆₀ reached 0.2. Cell density was determined after 8 h of growth