title: Effects of polarization in the presence and absence of biocides on biofilms in a simulated paper machine water.
abstract: The antifouling potential of electric polarization combined and not combined with biocides was studied in nonsaline warm water with high organic content. Deinococcus geothermalis is a bacterium known for forming colored biofilms in paper machines and for its persistence against cleaning and chemical treatments. When D. geothermalis biofilms grown for 24 h in simulated paper machine water were exposed to cathodic or cathodically weighted pulsed polarization at least 60% (P < 0.05) of the biofilms were removed from stainless steel (AISI 316L). Biofilm removal by 25 ppm (effective substances 5-25 ppm) of oxidizing biocides (bromochloro-5,5-dimethylhydantoin, 2,2-dibromo-2-cyanoacetamide, peracetic acid) increased to 70% when combined with cathodically weighted pulsed polarization. Using a novel instrument that allows real-time detection of reactive oxygen species (ROS) we showed that the polarization program effective in antifouling generated ROS in a pulsed manner on the steel surface. We thus suggest that the observed added value of oxidative biocides combined with polarization depended on ROS. This suggestion was supported by the finding that a reductive biocide, methylene bisthiocyanate, counteracted the antifouling effect of polarization.
authors: Department of Food and Environmental Sciences, University of Helsinki, P.O. Box 56, 00014 Helsinki, Finland. Minna.Peltola@helsinki.fi
authors: Minna
authors: M
authors: Peltola
authors: Teemu
authors: T
authors: Kuosmanen
authors: Hanna
authors: H
authors: Sinkko
authors: Niina
authors: N
authors: Vesalainen
authors: Martti
authors: M
authors: Pulliainen
authors: Päivi
authors: P
authors: Korhonen
authors: Kirsi
authors: K
authors: Partti-Pellinen
authors: Jari P
authors: JP
authors: Räsänen
authors: Juha
authors: J
authors: Rintala
authors: Marko
authors: M
authors: Kolari
authors: Hannu
authors: H
authors: Rita
authors: Mirja
authors: M
authors: Salkinoja-Salonen
mesh_terms: D018441:Biofilms / Q000187:drug effects; D057219:Biofouling; D034301:Deinococcus / Q000187:drug effects; D004202:Disinfectants / Q000494:pharmacology*; D055664:Electrochemical Techniques; D006801:Humans; D010209:Paper; D013193:Stainless Steel; D014871:Water Microbiology
chemical_list: D004202:Disinfectants; D013193:Stainless Steel