Effects of Ultraviolet LED on Bacteria

Abstract

Sterilization technology is absolutely essential for our daily life. For example, it is used for water and sewerage system, foods, and medicine. Method that widely used for sterilization are using drug, heating, ultraviolet (UV) radiation, and ozone. Chlorine is used extensively in sterilization because of its easiness and low cost. Using chlorine has some adverse effects such as alteration of quality of the target. Also it is bad for environment discharge water sterilized by drug to rivers and oceans. Conventional method for UV sterilization is using UV lamps. It is used to sterilize workspaces and tools used in biology laboratories and medical facilities. Low pressure mercury-vapor lamps emit 254 nm wavelength of UV which coincides very well with peaks of the germicidal effectiveness curve (i.e., effectiveness for UV absorption by DNA). Low pressure mercury-vapor lamps contains mercury and it has harmful effects to an environment and human body. In this study, we investigate effects of high-intensity ultraviolet light-emitting diode (UV LED) on E. coli and Vibrio parahaemolyticus. Aside from mercury-free, UV LED is low consumption. Exposure time of the UV is varied from 5 to 60 minutes. The wavelength of UV LED used is 365nm, its output is 15mW, and exposure distance between the UV LED and bacteria is 20mm. The result showed that germicidal effects for 100% of E.coli and 100% of Vibrio parahaemolyticus took 30 minutes and 10 minutes, respectively. These results suggest that the UV LED has sterilized effects.