title: Combination of selected enzymes with cetyltrimethylammonium bromide in biofilm inactivation, removal and regrowth.
abstract: Enzymes are considered an innovative and environmentally friendly approach for biofilm control due to their lytic and dispersal activities. In this study, four enzymes (β-glucanase, α-amylase, lipase and protease) were tested separately and in combination with the quaternary ammonium compound cetyltrimethylammonium bromide (CTAB) to control flow-generated biofilms of Pseudomonas fluorescens. The four enzymes caused modest reduction of biofilm colony forming units (CFU). Protease, β-glucanase and α-amylase also caused modest biofilm removal. CTAB combined with either β-glucanase or α-amylase increased biofilm removal. Its combination with either β-glucanase or protease increased CFU reduction. However, CTAB-protease combination was antagonist in biofilm removal. Long-term effects in biofilm mass reduction were observed after protease exposure. In contrast, biofilms treated with β-glucanase were able to regrow significantly after exposure. Moreover, short-term respirometry tests with planktonic cells were performed to understand the effects of enzymes and their combination with CTAB on P. fluorescens viability. Protease and lipase demonstrated antimicrobial action, while α-amylase increased bacterial metabolic activity. The combination of CTAB with either protease or α-amylase was antagonistic, decreasing the antimicrobial action of CTAB. The overall results demonstrate a modest effect of the selected enzymes in biofilm control, either when applied alone or each one in combination with CTAB. Total biofilm removal or CFU reduction was not achieved and, in some cases, the use of enzymes antagonized the effects of CTAB. The results also propose that complementary tests, to characterize biofilm integrity and microbial viability, are required when someone is trying to assess the role of novel biocide - enzyme mixtures for effective biofilm control.
authors.affiliation: LEPABE, Department of Chemical Engineering, Faculty of Engineering (FEUP), University of Porto, Rua Dr. Roberto Frias, s/n, 4200-465 Porto, Portugal; Water Desalination and Reuse Center (WDRC), Division of Biological and Environmental Science and Engineering (BESE), King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia.
authors.forename: Paula A
authors.initials: PA
authors.lastname: Araújo
authors.affiliation: LEPABE, Department of Chemical Engineering, Faculty of Engineering (FEUP), University of Porto, Rua Dr. Roberto Frias, s/n, 4200-465 Porto, Portugal.
authors.forename: Idalina
authors.initials: I
authors.lastname: Machado
authors.affiliation: LEPABE, Department of Chemical Engineering, Faculty of Engineering (FEUP), University of Porto, Rua Dr. Roberto Frias, s/n, 4200-465 Porto, Portugal.
authors.forename: Ana
authors.initials: A
authors.lastname: Meireles
authors.affiliation: Water Desalination and Reuse Center (WDRC), Division of Biological and Environmental Science and Engineering (BESE), King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia.
authors.forename: TorOve
authors.initials: T
authors.lastname: Leiknes
authors.affiliation: LEPABE, Department of Chemical Engineering, Faculty of Engineering (FEUP), University of Porto, Rua Dr. Roberto Frias, s/n, 4200-465 Porto, Portugal.
authors.forename: Filipe
authors.initials: F
authors.lastname: Mergulhão
authors.affiliation: LEPABE, Department of Chemical Engineering, Faculty of Engineering (FEUP), University of Porto, Rua Dr. Roberto Frias, s/n, 4200-465 Porto, Portugal.
authors.forename: Luís F
authors.initials: LF
authors.lastname: Melo
authors.affiliation: LEPABE, Department of Chemical Engineering, Faculty of Engineering (FEUP), University of Porto, Rua Dr. Roberto Frias, s/n, 4200-465 Porto, Portugal. Electronic address: mvs@fe.up.pt.
authors.forename: Manuel
authors.initials: M
authors.lastname: Simões
mesh_terms: D000890:Anti-Infective Agents / Q000494:pharmacology; D018441:Biofilms / Q000187:drug effects*; D002593:Cetrimonium Compounds / Q000494:pharmacology*; D050296:Microbial Viability; D010447:Peptide Hydrolases / Q000494:pharmacology; D011551:Pseudomonas fluorescens / Q000187:drug effects*; D013193:Stainless Steel; D000516:alpha-Amylases / Q000494:pharmacology
chemical_list: D000890:Anti-Infective Agents; D002593:Cetrimonium Compounds; D013193:Stainless Steel; D000516:alpha-Amylases; D010447:Peptide Hydrolases
keywords: Antimicrobial quenching; Biofilm control; Cleaning; Disinfection; Enzymes; Flow-generated biofilms; Pseudomonas fluorescens