Development of teaching materials to visualize various scientific phenomena such as the bactericidal action of ultraviolet rays with bioassays using lactic acid bacteria

Abstract

We developed a simple environmental sensor using lactic acid bacteria isolated from a lactic acid beverage that could be used to visualize and teach high school students about the bactericidal action of ultraviolet radiation. We sprayed a dilute solution of Lactobacillus bulgaricus OLL1073R-1 and Lacticaseibacillus casei Shirota onto a Petri dish containing De Man–Rogosa–Sharpe (MRS) agar, covered half of the dish with aluminum foil, irradiate with sunlight, and cultured for 48 hours at 40°C. We compared of the number of colonies on the part of the plate exposed and not exposed to sunlight. This simple environmental assay can improve the awareness and understanding of high school students regarding the benefits and harms of ultraviolet rays.