Selection of a New Highly Resistant Strain for Malolactic Fermentation under Difficult Conditions

  • R. Guzzon Fondazione Edmund Mach, Via Edmund Mach 1, 38010 San Michele all’Adige (TN), Italy
  • E. Poznanski Fondazione Edmund Mach, Via Edmund Mach 1, 38010 San Michele all’Adige (TN), Italy
  • L. Conterno Fondazione Edmund Mach, Via Edmund Mach 1, 38010 San Michele all’Adige (TN), Italy
  • P. Vagnoli Lallemand Italiana, Castel d’Azzano (VR), Italy
  • S. Krieger-Weber Lallemand Inc., Canada
  • A. Cavazza Fondazione Edmund Mach, Via Edmund Mach 1, 38010 San Michele all’Adige (TN), Italy

Abstract

Malolactic fermentation (MLF) is a biological process that contributes to wine quality, but it is frequently affected
by various vinification conditions. Resistance to four wine-limiting factors was studied with respect to 10 Oenococcus
oeni strains in order to select a suitable strain for performing reliable MLF in difficult wines. Resistance to low
fermentation temperature, high SO2 and/or ethanol concentration, and low pH were assayed in laboratory tests. A
pool of the most resistant strains was used in a set of laboratory MLFs. At the end of fermentation, the dominant
strains were identified by RAPD-PCR. The PN4 strain was found to be dominant in the majority of cases and under
the most detrimental wine conditions, and it was therefore chosen as the single-strain inoculum for the subsequent
MLF trials. The effectiveness of the PN4 strain was confirmed in a series of MLFs carried out in three different
countries under experimental and industrial conditions. It accomplished MLF in wines with up to 15.8% ethanol,
pH as low as 3.0, 60 mg/L of free SO2, and in fermentation temperatures below 17ºC. Our findings indicate that the
O. oeni PN4 strain could be an effective starter, guaranteeing regular and reliable MLF fermentation.
Published
2016-12-12
Section
Articles