Microorganisms Photocatalytic Inactivation on Ag3PO4 Sub-Microcrystals Under WLEDs Light Source

In this article, we report the silver orthophosphate (Ag3PO4) photocatalytic inactivation properties on strains Gram-positive Saprophyte B. subtilis, a diploid fungus Candida albicans and Gram-negative Pseudomonas aeruginosa, using as irradiation source white-light-emitting diodes (WLEDs) with luminous flux (phi v) of 1.3 x 10(3) Lumens and relative power density of 15 mW m(-2). Microorganisms death curves and the kinetic constants (K-d) indicated that the inhibitory effect of the Ag3PO4 under WLEDs irradiation is well pronounced to C. albicans (6.6 x 10(-2) min(-1)) in relation to P. augenosas (4.6 x 10(-2) min(-1)) and B. subitilis (2.5 x 10(-2) min(-1)). Decimal reduction time (D-t) were 34.4 min to C. albicans, 50.1 min P. augenosas and 92.1 min to B.subitilis. The micrographs obtained by scanning electron microscopy with field emission gun (SEM-FEG) demonstrated that there was cell wall permeability and consequently total rupture in the C. albicans, suggesting the lipid peroxidation phenomenon and protein oxidation promoted by the presence of reactive oxygen species (ROS). Furthermore, it was observed the A(g3)PO(4) when irradiated by WLEDs demonstrates important sporicidal activity in related to B. subtilis, promoting the endospore wall rupture.

Automated summary

This article reports on the photocatalytic inactivation properties of silver orthophosphate (Ag3PO4) on different strains of bacteria under white LED illumination and the underlying mechanisms. The inhibitory effect of Ag3PO4 was most pronounced on Candida albicans, followed by Pseudomonas aeruginosa and B. subtilis. Additionally, Ag3PO4 induced changes in cell wall permeability and rupture in the microorganisms.