Fig. 2

Assessment of butanol tolerance of σ⁷⁰ mutants B8, D3 and WT. a The growth of B8, D3 and WT in the presence of different concentrations of n-butanol (1.2–2.2 %, v/v). All mutant strains were cultured in 24-well plates at 37 °C for 8 h. Different concentrations of n-butanol were added at 0.2 OD₆₆₀. Three biological replicates were performed. b Butanol shock treatment of σ⁷⁰ mutant B8 and WT. The strains viability was tested after treatíng without or with 3.0 % (v/v) butanol. Sequential tenfold dilution of cell cultures was spotted on LB agar and incubated at 37 °C overnight