Skin Bacteria Mediate Glycerol Fermentation to Produce Electricity and Resist UV-B

Abstract

Bacteria that use electron transport proteins in the membrane to produce electricity in the gut microbiome have been identified recently. However, the identification of electrogenic bacteria in the skin microbiome is almost completely unexplored. Using a ferric iron-based ferrozine assay, we have identified the skin Staphylococcus epidermidis (S. epidermidis) as an electrogenic bacterial strain. Glycerol fermentation was essential for the electricity production of S. epidermidis since the inhibition of fermentation by 5-methyl furfural (5-MF) significantly diminished the bacterial electricity measured by voltage changes in a microbial fuel cell (MFC). A small-scale chamber with both anode and cathode was fabricated in order to study the effect of ultraviolet-B (UV-B) on electricity production and bacterial resistance to UV-B. Although UV-B lowered bacterial electricity, a prolonged incubation of S. epidermidis in the presence of glycerol promoted fermentation and elicited higher electricity to suppress the effect of UV-B. Furthermore, the addition of glycerol into S. epidermidis enhanced bacterial resistance to UV-B. Electricity produced by human skin commensal bacteria may be used as a dynamic biomarker to reflect the UV radiation in real-time.

eDNA-Mediated Cutaneous Protection Against UVB Damage Conferred by Staphylococcal Epidermal Colonization

“…Under this premise, it should be noted that staphylococci possess many oxidative stress resistance mechanisms, including ROS-detoxifying proteins and membrane lipids oxidation involvement [ 50 , 51 ]. More recent data show that S. epidermidis can resist UV damage via glycerol fermentation [ 52 ], where a product of this fermentation process, butyric acid, was shown to reduce UVB-induced cutaneous proinflammatory cytokine production in a murine model [ 53 ]. These observations may, of course, be part of the contributors to the observed cutaneous UVB protection in the present study.…”

Electricity-producing Staphylococcus epidermidis counteracts Cutibacterium acnes

“…The voltage difference (mV) against time (min) was monitored by a digital multimeter (Lutron, DM-9962SD, Sydney, Australia). The voltage was recorded every 10 s to plot a graph of voltage against time 34 .…”

Electricity-Producing Staphylococcus Epidermidis Counteracts Cutibacterium Acnes

“…The voltage difference (mV) against time (min) was monitored by a digital multimeter (Lutron, DM-9962SD, Sydney, Australia). The voltage was recorded every 10 sec to plot a graph of voltage against time 34 .…”