Rapid biosynthesis of fluorescent CdSe QDs in Bacillus licheniformis and correlative bacterial antibiotic change...

Cadmium selenide (CdSe) quantum dots (QDs) were biosynthesized rapidly in 18 h in Bacillus licheniformis ATCC 11946 (B. licheniformis); this process benefited from the cellular machinery of bacteria metal metabolism, in which inorganic Na₂ SeO₃ and CdCl₂ were chosen as raw materials to produce high quality CdSe QDs by a designed two-step protocol. Research outcomes demonstrated that the purified CdSe QDs possessed maximum fluorescence intensities at weak alkalinity solutions and had good fluorescence stabilities at 4°C as well as at room temperature after standing for 1 week. Glutathione (GSH) concentration and superoxide dismutase (SOD) content, both of which were reported to be greatly related to biosynthetic activities in some bacterial matrices, were monitored during the biosynthetic process in B. licheniformis. Bacterial resistance research further showed that the change in rates in bacterial inhibition zone diameter to seven different antibiotics was less than 9% after B. licheniformis was used to manufacture CdSe QDs, showing a relative lower environmental risk in short-term heavy metal exposure.