Fig. 1From: DNA microarray of global transcription factor mutant reveals membrane-related proteins involved in n-butanol tolerance in Escherichia coli Screening for σ70 mutants with high butanol tolerance in the a first round and b second round. All mutant strains were cultured in 24-well plates at 37 °C for 8 h, and 0.5 % (v/v) n-butanol was added at 0.2 OD660 Back to article page