title: Experimental Study of Membrane Fouling during Crossflow Microfiltration of Yeast and Bacteria Suspensions: Towards an Analysis at the Microscopic Level.
abstract: Microfiltration of model cell suspensions combining macroscopic and microscopic approaches was studied in order to better understand microbial membrane fouling mechanisms. The respective impact of Saccharomyces cerevisiae yeast and Escherichia coli bacteria on crossflow microfiltration performances was investigated using a multichannel ceramic 0.2 µm membrane. Pure yeast suspensions (5 µm ovoid cells) and mixtures of yeast and bacteria (1 to 2.5 µm rod shape cells) were considered in order to analyse the effect of interaction between these two microorganisms on fouling reversibility. The resistances varied significantly with the concentration and characteristics of the microorganisms. Membrane fouling with pure yeast suspension was mainly reversible. For yeast and bacteria mixed suspensions (6 g L-1 yeast concentration) the increase in bacteria from 0.15 to 0.30 g L-1 increased the percentage of normalized reversible resistance. At 10 g L-1 yeast concentration, the addition of bacteria tends to increase the percentage of normalized irreversible resistance. For the objective of performing local analysis of fouling, an original filtration chamber allowing direct in situ observation of the cake by confocal laser scanning microscopy (CLSM) was designed, developed and validated. This device will be used in future studies to characterize cake structure at the microscopic scale.
authors: LRAE (Laboratoire Radio analyses et Environnement), Ecole nationale d'ingénieurs de Sfax., Sfax BP3038, Tunisie. philippe.schmitz@insa-toulouse.fr.
authors: Ines Ben
authors: IB
authors: Hassan
authors: LAA (Laboratoire Analyses Alimentaires), Ecole nationale d'ingénieurs de Sfax., Sfax BP3038, Tunisie. ennouri_monia@yahoo.fr.
authors: Monia
authors: M
authors: Ennouri
authors: Université de Toulouse, INSA, UPS, INP, LISBP, 135 Avenue de Rangueil, Toulouse F-31077, France. christine.lafforgue@insa-toulouse.fr.
authors: Christine
authors: C
authors: Lafforgue
authors: Université de Toulouse, INSA, UPS, INP, LISBP, 135 Avenue de Rangueil, Toulouse F-31077, France. philippe.schmitz@insa-toulouse.fr.
authors: Philippe
authors: P
authors: Schmitz
authors: LRAE (Laboratoire Radio analyses et Environnement), Ecole nationale d'ingénieurs de Sfax., Sfax BP3038, Tunisie. moneim.ayadi@enis.rnu.tn.
authors: Abdelmoneim
authors: A
authors: Ayadi