Polyphenols from olive mill waste affect biofilm formation and motility in Escherichia coli K12

Genome-wide transcriptional analysis was performed on E. coli K12 exposed to 1 mg/ml of olive vegetation water phenolic extract (OVWPE) in planktonic condition. Three groups of samples were considered: P group (three replicate cultures with OVWPE extract diluted in ethanol 20%), E group (three replicate cultures with ethanol 20% alone) C group (three control replicate cultures). 1 ml of VWPE extract (1 mg/ml), 1 ml of ethanol 20% and 1 ml of LB broth were added respectively to the three groups when the OD600 of each culture reached 0.4. Cultures were sampled (2 ml) at the time of treatment (t1), 20 (t2) and 40 (t3) minutes after treatment.