Effectiveness of photoelectrocatalysis treatment for the inactivation of Candida parapsilosis sensu stricto in planktonic cultures and biofilms

Abstract

Photoelectrocatalysis (PEC) has become an attractive technology to disinfect microorganisms from aqueous environments because of its ability to degrade microorganisms without producing any harmful by-products. PEC methodology was applied to inactivate Candida parapsilosis sensu stricto in planktonic and biofilm cells, and its efficiency was compared to that of photolytic and photocatalytic treatment. In the case of planktonic (free-floating) cells, PEC promoted the inactivation of 106 CFU mL-1 after 3 min of treatment, and the addition of silver nanoparticles to the Ti/TiO2 electrodes had virtually no effect on the disinfection period, although it caused a decrease by a factor of 1.5 in the mineralization efficiency. After 60, 10 and 60 min of treatment, PEC methodology reduced 106 CFU mL-1 on fungal biofilms and provided 71, 91 and 92% mineralization for biofilm cells performed on polyvinyl chloride (PVC), silicone, and polytetrafluoroethylene (PTFE), respectively. These results indicated that PEC is a promising process for disinfection of water contaminated with C. parapsilosis sensu stricto in both planktonic and biofilm cells.