Departament de Bioquímica i Biotecnologia, Facultat d'Enologia, Universitat Rovira i Virgili, C/Marcel·lí Domingo s/n 43007, Tarragona, Catalonia, Spain.
Int J Food Microbiol. 2010 Nov 15;144(1):88-95. doi: 10.1016/j.ijfoodmicro.2010.08.032. Epub 2010 Sep 7.
The correct performance of wine malolactic fermentation (MLF) depends on the metabolic characteristics of the Oenococcus oeni strain/s responsible for this process. This study characterizes four O. oeni strains, which behave differently in terms of malolactic performance, the citric acid use related to acetic acid production, and stress adaptation. Metabolic evolution and its associated enzymatic activities were studied and the transcriptional response of the genes related to MLF, citrate metabolism and stress response was compared among strains. A higher initial expression of both the malolactic enzyme and the encoding gene mleA may be related to faster MLF. The initial transcriptional levels of citrate lyase (citE) proved indicative of early citrate consumption. Moreover, the strains that performed best in wine-like conditions presented a much higher relative expression of several stress responsive genes, particularly hsp18, clpP, ctsR and rmlB. Finally, an inter-strain comparison of the transcriptional levels of selected genes at different times during MLF proved a useful tool in characterizing strains based on their metabolic behaviour.
葡萄酒苹果酸-乳酸发酵（MLF）的正确进行取决于负责该过程的片球菌（Oenococcus oeni）菌株的代谢特性。本研究对四种片球菌菌株进行了表征，这些菌株在苹果酸-乳酸性能、与乙酸生成相关的柠檬酸利用以及应激适应方面表现不同。研究了代谢进化及其相关的酶活性，并比较了与 MLF、柠檬酸代谢和应激反应相关的基因的转录反应。较高的苹果酸-乳酸酶和编码基因 mleA 的初始表达可能与更快的 MLF 相关。柠檬酸裂解酶（citE）的初始转录水平表明早期柠檬酸的消耗。此外，在葡萄酒样条件下表现最好的菌株表现出更高的几种应激响应基因的相对表达水平，特别是 hsp18、clpP、ctsR 和 rmlB。最后，在 MLF 过程的不同时间对选定基因的转录水平进行菌株间比较，证明是基于其代谢行为对菌株进行表征的有用工具。
