A new sensor method for studying the effect of surfactants on the growth of Pseudomonas aeruginosa

A new sensor method based on series piezoelectric quartz crystal (SPQC) sensing technique was proposed for studying the effect of surfactants on the growth of Pseudomonas aeruginosa in media. The frequency shift curves under different growth conditions were obtained and compared with each other. By fitting frequency shift (ΔF) curves, three kinetic parameters (μ_m, λ and A) were gained to describe the growth of microorganisms. When the ΔF became small and frequency detection time (FDT) prolonged, surfactants had an inhibitory effect to the growth of bacteria. At the same time, the lag time (λ) was prolonged; the maximum specific growth rate (μ_m) and the asymptote (A) were decreased. By using the proposed method, the influence of the concentration and ion type of surfactants, hydrophilic group and the number of ethoxyl of nonionic surfactants on the growth of bacteria was investigated in detail.