Abstract

ELGOULLI, Mourad et al. Effect of chemical compounds in water on surface properties and adhesion capacity of Pseudomonas aeruginosa and Escherichia coli in turbulent conditions. Water SA [online]. 2021, vol.47, n.4, pp.430-436. ISSN 1816-7950.  http://dx.doi.org/10.17159/wsa/2021.v47.i4.3859.

The aim of this study was to evaluate the effect of chemical compounds found in different water types on the physico-chemical properties of bacteria and the adhesion of two strains (Pseudomonas aeruginosa and Escherichia coli) to glass, PVC and stainless steel. P. aeruginosa and E. coli were exposed to two sterile water types (distilled water and tap water) for 3 h. Contact angle measurements were used to assess the surface properties of both strains and coupons of different materials. The hydrophobicity (∆G_iwl^p.a = 70mJ/m², ∆G_iwl^E.c = 49mJ/m²) and the electron donor properties (y_Pa = 106,81mJ/m², y_Ec = 74mJ/m²) of the bacterial strains seems to increase when exposed to sterile tap water compared to distilled water, while the electron acceptor property is largely unchanged (y⁺_p.a = 0,98mJ/m², y⁺_Ec = 0mJ/m²). The adhesion tests were carried out in a water circuit creating turbulence. The number of adhered cells was determined after their detachment from the coupons using an ultrasonic bath for 2 min. The findings showed that the type of water affects the adhesion of both strains, which is stronger in tap water than distilled water. A correlation test to determine the surface property that governs adhesion in these conditions, suggested that the adhesion is mainly governed by hydrophobicity.

Keywords : type of water; type of materials; bacterial adhesion; physicochemical properties.

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