Institute for Wine Biotechnology and Department of Viticulture and Oenology, Stellenbosch University, Stellenbosch, South Africa.
J Appl Microbiol. 2019 Nov;127(5):1490-1500. doi: 10.1111/jam.14401. Epub 2019 Aug 28.
This study investigated the influence of sugars (glucose and fructose) and pH on the gene expression of citE (citrate lyase β-subunit) and the subsequent formation of metabolites associated with citrate metabolism.
Different levels of glucose (2·5, 50 and 115 g l ), fructose (2·5, 50 and 115 g l ) and pH (3·0, 3·5, 4·0 and 5·0) were evaluated for their effect on citE expression in four different lactic acid bacteria strains. Two Oenococcus oeni strains and two Lactobacillus plantarum strains were used, of which one strain of each species screened positive for the citE gene. Among the factors tested, fructose had the biggest influence on the relative expression of citE in O. oeni. In addition, the citrate-positive strains produced high concentrations of diacetyl and acetoin.
This study gives an overview of how sugar, pH and different lactic acid bacteria strains influence citE gene expression and the formation of metabolites associated with citrate metabolism closely linked to malolactic fermentation (MLF).
These results can be used to make informed decisions regarding MLF when aiming to create a wine with a buttery aroma or not.
本研究旨在探讨糖（葡萄糖和果糖）和 pH 值对 citE（柠檬酸裂解酶 β 亚基）基因表达以及随后与柠檬酸代谢相关代谢物形成的影响。
在四种不同的乳酸菌菌株中，评估了不同葡萄糖（2.5、50 和 115 g l）、果糖（2.5、50 和 115 g l）和 pH 值（3.0、3.5、4.0 和 5.0）水平对 citE 表达的影响。使用了两株 Oenococcus oeni 菌株和两株 Lactobacillus plantarum 菌株，其中每种菌株的一株被筛选为 citE 基因阳性。在所测试的因素中，果糖对 O. oeni 中 citE 的相对表达影响最大。此外，柠檬酸阳性菌株产生了高浓度的双乙酰和乙酰基。
本研究概述了糖、pH 值和不同乳酸菌菌株如何影响 citE 基因表达以及与密切相关的柠檬酸代谢相关的代谢物的形成与苹果酸-乳酸发酵（MLF）。
这些结果可用于在旨在酿造具有黄油香气的葡萄酒或不酿造此类葡萄酒时，对 MLF 做出明智的决策。
