Figure 3.

The effect of UV-B on electricity generation from a 24 or 72 h period of S. epidermidis fermentation. (a) Media (M) alone or with 10⁷ CFU/mL bacteria (B) in the presence or absence of 2% glycerol (G) were incubated for 24 or 72 h. The color change of phenol red in media from red to yellow indicated the phenomenon of fermentation which was quantified by OD₅₆₂. (b) Electricity measured by voltage changes (mV) in an in vitro chamber was recorded for 20 min upon a UV-B dosage of 1 mJ/cm². The peak voltage of each group was quantified. Results are the mean ± SD from three independent experiments. ns = non-significant. * p < 0.05; *** p < 0.001 (two-tailed t-tests).