The potential of positively-charged cellulose sponge for malolactic fermentation of wine, using Oenococcus oeni

Malolactic fermentation (MLF) is a secondary bioconversion developed in som e wines involving malic acid decarboxylation. The induction of MLF in wine by cultures of free and immobilized Oenococcus oeni cells was investigated. This work reports on the effect of surface charges in the immobilization m aterial, a recently described fibrous sponge, as well as the pH and the com position of the media where cells are suspended. A chemical treatment provi ded positive charge to the sponges (DE or DEAE) and gave the highest cell l oadings and subsequent resistance to removal. Preculture media to grow the malolactic bacteria before the immobilization procedure were also evaluated . We have established favorable conditions for growth (Medium of Preculture ), suspension solution (Tartrate-Phosphate Buffer), suspension pH (3.5-5.5) and immobilization matrix (DE or DEAE cellulose sponge) to induce MLF in r ed wine. The use of a semi-continuous system permitted a high-efficiency ma lic acid conversion by 2 X 10(9) cfu sponge(-1) in at least four subsequent batch fermentations. (C) 2001 Elsevier Science Inc. All rights reserved.