For the analysis of Kþ leakage from the bacterial cells, the illuminated
bacterial suspension was collected at different treatment
time and centrifuged at 12,000 g and 4 C for 10 min. The supernatant
was used for assays. The Kþ content in the supernatant was
determined by VG Inductively Coupled Plasma Mass Spectrometer
(ICP-MS, Plasma Quad 3)