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The goal of this study was to develop conditional flocculant yeasts for use in the alcohol fermentation industry. Promoters were constructed to completely repress gene transcription in the presence of sugar and to support strong expression after the exhaustion of this compound. A fusion of regulatory regions of the ADH2 promoter with the FLO5 core promoter was constructed to regulate the FLO5 gene. This construct was inserted into multicopy plasmids and transformed into laboratory strains of Saccharomyces cerevisiae, whereby the transformed cells were selected by sedimentation from the bulk medium after sugar exhaustion, without decreasing ethanol production. The ADH2-FLO5 region was converted into an integrative cassette to disrupt the CAN1 gene in industrial yeast strains. Transformed cells became resistant to canavanine and demonstrated conditional flocculation. Although ethanol production was significantly decreased in the industrial transformants, this development reveals a promising technology for the substitution of centrifugation in industrial ethanol production.

A.P.L. D ELAMARE, S . E CHEVERRIGARAY, K .R. D UARTE, L .H. G OMES A ND S .O.P. C OSTA. 2002. Aims: to develop a monoclonal antibody (MAb) for the rapid detection of Aeromonas hydrophila in human faeces. Methods and Results: A monoclonal antibody with strong specificity against Aer. hydrophila was obtained by the fusion of myeloma cells and splenocytes of a mouse immunized with vegetative cells of Aer. hydrophila ATCC 7966, followed by a two-step selection against other species of the genera. ELISA analyses revealed that MAb 5F3 strongly reacts with all the Aer. hydrophila strains evaluated, showing a just basal reactivity against other species of the genera, especially Aer. sobria and Aer. caviae. Conclusions: MAb 5F3 was characterized as an IgG that recognized a polypeptide of approximately 110 kDa. Significance and Impact of the Study: This MAb could be used to detect Aer. hydrophila in human stool samples.