Inactivation of a wild isolated Klebsiella pneumoniae by photo-chemical processes: UV-C, UV-C/H2O2 and UV-C/H2O2/Fe3+

Abstract

Shrimp (Litopenaeus vannamei) farming is an important economic activity in several countries. Pathogens in shrimp farms and its e uents pose a potential hazard for both humans and shrimps. Wild strains of bacteria were characterized in a shrimp farm, and Klebsiella pneumoniae was chosen as a good indicator due to its presence in the pond and the e uent and its resistance to antibiotics. Di erent photochemical processes (UV/H2O2, UV/ H2O2/Fe3+) were tested for inactivation of wild isolated K. pneumoniae and compared to UV-C radiation. By kinetic modelling, a kmax equal to 0.43 s−1 was obtained for UV-C treatment. After optimizing the cited pro- cesses, ranging [H2O2]: 10–30 mg·l−1; an optimal [H2O2] of 10 mg·l−1 was found, increasing kmax on 13.63% compared to UV-C. This optimal concentration was tested for UV/H2O2/Fe3+ process; ranging [Fe3+]: 2–20 mg·l−1. The highest yield was obtained by a [H2O2]:[Fe3+] = 10:2, which leads to 4-Log reduction in 12.88 s of treatment. Moreover, resistance of K. pneumoniae was compared to Escherichia coli. The latter proved to be more sensitive despite its similar cellular structure. Results suggested that the photochemical processes could enhance disinfection e ciency, especially for photo-assisted Fenton-like process in most resistant bacteria.