Lactic acid bacteria associated with wine grapes from several Australian vineyards

Abstract

Aims: The detection and isolation of lactic acid bacteria by enrichment methods from wine grapes cultivated in vineyards located in New South Wales, Australia. Methods and Results: Enrichment cultures in de Man, Rogosa and Sharpe (MRS) broth, MRS + ethanol (5%), MRS broth supplemented with 15% (v/v) tomato juice (MRST), pH 5·5 and 3·5 and autoenrichment in grape juice homogenate were used to detect lactic acid bacteria on wine grapes. Bacteria were isolated from enrichment cultures by plating onto MRS and MRST agar and identified by 16S rDNA sequence analysis and phenotypical methods. A molecular method, PCR‐denaturing gradient gel electrophoresis (DGGE) was also used to examine the bacteria that developed in enrichment cultures. Species of Lactobacillus, Enterococcus, Lactococcus and Weissella were detected in enrichments by plating and PCR‐DGGE. Other bacteria (Sporolactobacillus, Asaia, Bacillus ssp.) were also found in some enrichment cultures. The principal malolactic bacterium, Oenococcus oeni, was not isolated. Conclusions: The incidence and populations of lactic acid bacteria on wine grapes were very low. Damaged grape berries showed a greater presence of these bacteria than undamaged berries. The diversity of bacterial species isolated from the grapes was greater than those previously reported and represented both lactic acid bacteria and nonlactic acid bacteria. Some of these bacteria (i.e. Lactobacillus lindneri, Lactobacillus kunkeei) could be detrimental to wine production. Oenococcus oeni was not found on grapes, but its recovery could be obscured by overgrowth from other species. Significance and Impact of the Study: Lactic acid bacteria are significant in wine production because they conduct the malolactic fermentation and cause stuck or sluggish alcoholic fermentation and wine spoilage. This study investigates wine grapes as a potential source of these bacteria.

Weissella uvarum sp. nov., isolated from wine grapes

“…LAB can significantly improve wine quality by conducting malolactic fermentation (Lonvaud-Funel, 1999), while they may also cause wine spoilage through the production of undesirable secondary metabolites (Liu, 2002). Grapes represent an untapped reservoir for LAB species involved in winemaking; therefore, grape bacterial diversity has systematically attracted scientific attention (Bae et al, 2006;Nisiotou et al, 2011). LAB species associated with grapes mainly belong to the genera Lactobacillus and Leuconostoc (Bae et al, 2006;and citations therein).…”

“…Grapes represent an untapped reservoir for LAB species involved in winemaking; therefore, grape bacterial diversity has systematically attracted scientific attention (Bae et al, 2006;Nisiotou et al, 2011). LAB species associated with grapes mainly belong to the genera Lactobacillus and Leuconostoc (Bae et al, 2006;and citations therein). As yet, Weissella paramesenteroides is the only species of the genus Weissella that has been encountered in grape must or wine (Bae et al, 2006;König & Fröhlich, 2009).…”

“…LAB species associated with grapes mainly belong to the genera Lactobacillus and Leuconostoc (Bae et al, 2006;and citations therein). As yet, Weissella paramesenteroides is the only species of the genus Weissella that has been encountered in grape must or wine (Bae et al, 2006;König & Fröhlich, 2009). …”

Characterization of the tyramine-producing pathway in Sporolactobacillus sp. P3J

“…Sporolactobacilli have been associated with fermentation starters for Asian alcoholic beverages (Yanagida et al, 1997), wine grapes (Bae et al, 2006) and the associated environments Chang et al, 2008), as well as spoiled orange juice (Fujita et al, 2010) and the extreme environment of sugar thick juice (Justé et al, 2008). To our knowledge, this study is the first description of a bacterium associated with cider production that belongs to the Sporolactobacillus genus.…”

Microbial Succession in Spontaneously Fermented Grape Must Before, During and After Stuck Fermentation

“…Many investigations describe the presence of organisms in the grape must, although most studies were restricted to one group of organisms (e.g. yeasts, lactic acid bacteria, acetic acid bacteria) and/or to one stage during the fermentation (Cocolin et al, 2000;Mills et al, 2002;Bae et al, 2006;Renouf et al, 2007). To our knowledge, no studies describe the microbial (yeasts and bacteria) succession in stuck grape must over several months.…”