Role of hydrophobicity in adhesion of wild yeast isolated from the ultrafiltration membranes of an apple juice processing plant

Abstract

The role of cell surface hydrophobicity in the adhesion to stainless steel (SS) of 11 wild yeast strains isolated from the ultrafiltration membranes of an apple juice processing plant was investigated. The isolated yeasts belonged to four species: Candida krusei (5 isolates), Candida tropicalis (2 isolates), Kluyveromyces marxianus (3 isolates) and Rhodotorula mucilaginosa (1 isolate). Surface hydrophobicity was measured by the microbial adhesion to solvents method. Yeast cells and surfaces were incubated in apple juice and temporal measurements of the numbers of adherent cells were made. Ten isolates showed moderate to high hydrophobicity and 1 strain was hydrophilic. The hydrophobicity expressed by the yeast surfaces correlated positively with the rate of adhesion of each strain. These results indicated that cell surface hydrophobicity governs the initial attachment of the studied yeast strains to SS surfaces common to apple juice processing plants.

In siturheology of yeast biofilms

“…These results show that C. krusei predominated in biofilms formed on SS disks in both hydrodynamic conditions. In the study by Tarifa et al (2013) C. krusei represented the majority of the isolates from UF membrane samples, showing the adaptive advantage of this species. Brugnoni et al (2007) reported similar results where C. krusei, isolated from a large-scale apple juice processing plant, presented the highest covered surface on SS compared with other yeasts.…”

“…As described in a previous study (Tarifa et al 2013) the resident community on biofouled UF membranes used in the apple juice processing industry was composed of four yeast species. In order to gain an insight into their behavior, a mixture of yeast species was examined under different hydrodynamic forces and exposure times.…”

“…The yeast strains used in this work were isolated from the surfaces of polyvinylidene-fluoride ultrafiltration (UF) membranes, obtained from a large-scale apple juice processing industry located in Argentina (Tarifa et al 2013). These yeasts had survived repeated cycles of production and membrane cleaning procedures.…”

“…The typical hydrodynamic condition prevailing in the membranes of clarified apple juice manufacturing plants is turbulent flow (Yazdanshenas et al 2005;Tarifa et al 2013). In order to adhere to surfaces and subsequently to form biofilms, yeast cells grown in high-velocity flowing systems must overcome shear stress at the fluid-surface interface.…”

“…In previous studies, Brugnoni et al (2007) and Tarifa et al (2013), reported on the adhesion and biofilm formation of yeasts isolated from apple juice processing equipment. One of these yeasts, a strain of Candida krusei, was capable of colonizing stainless steel and forming biofilms under laminar, transitional, and turbulent flow (Brugnoni et al 2011a(Brugnoni et al , 2011b2012).…”