A bacterial strain B. Subtilis (Accession: JN165753) (isolated from
the South Lake, Wuhan, China) was irradiated by UV (power 15 W,
irradiation distance 30 cm, irradiation time 70 s) to induce random
mutations. A mutant ZN0871v11 was selected by the highest capacity
of adsorbing Direct Blue 2B dye. Mutant ZN0871v11 was
further genetically engineered by reforming the cell wall peptidoglycan
synthesis pathway (to knock out the yqfY and spo0A genes).
The clone is called GEBS. The GEBS clone was inoculated in LB
medium (Tryptone 1.0 g, yeast extract 0.5 g, NaCl 0.5 g, H2O
100 mL), and grown at 37 C for 48 h. The resulting culture was
centrifuged at 7280 g for 5 min, and the supernatant was discarded.
Cell pellets were resuspended and boiled for 5 min, washed
3 times with distilled water, and then added to the samples to be
treated in predetermined proportions. The ratio of wetweight (WT)
and dry weight of the cells is 6.88:1.