Flocculation and cell surface characterization of Kloeckera apiculata from wine.
OBJECTIVE
To characterize and analyze the flocculation phenomenon of Kloeckera apiculata mc1 from Argentinian wine to understand the cell-cell interaction pattern.


RESULTS
Kloeckera apiculata mc1 possess intense cell-cell interactions in MYPG medium (0.5% malt extract, 1% yeast extract, 2% glucose, 2% peptone), pH 5.5 by shaking at 25 degrees C. Optimum flocculation is observed at pH 4.5 in the presence of 3 mmol l-1 Ca2+. The flocculation is induced by peptone and malt extract and not by yeast extract and is reversed by 50 mmol l-1 galactose or lactose. The flocculation is highly susceptible to pronase, chymotrypsine and proteases types IV and XXVII and is partially resistant to trypsin. The electronic microscopy shows that the cells are attached to each other along their sides by fine hair-like threads.


CONCLUSIONS
The mechanism of flocculation of K. apiculata mc1 is mediated by protein-carbohydrate interaction, stabilized by Ca2+.


CONCLUSIONS
The use of selected pure yeast inocula of known ability is preferred to wine elaboration, therefore the indigenous flora must be avoided and the flocculation of K. apiculata could be an economic method to do it.
Farías
M E
ME
Centro de Referencia para Lactobacilos (CERELA), and Facultad de Bioquímica, Química y Farmacia, Universidad Nacional de Tucumán, 4000 Tucumán, Argentina.
Manca de Nadra
M C
MC
D002118:Calcium / Q000494:pharmacology; D002241:Carbohydrates / Q000494:pharmacology; D003470:Culture Media; D004798:Enzymes / Q000494:pharmacology; D005427:Flocculation; D005516:Food Microbiology; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007218:Industrial Microbiology; D008854:Microscopy, Electron; D014920:Wine / Q000382:microbiology*; D015003:Yeasts / Q000187:drug effects / Q000502:physiology* / Q000648:ultrastructure
D002241:Carbohydrates; D003470:Culture Media; D004798:Enzymes; D002118:Calcium