Matthews Angela, Grbin Paul R, Jiranek Vladimir
School of Agriculture, Food and Wine, The University of Adelaide, PMB 1, Glen Osmond, South Australia, 5064, Australia,
Appl Microbiol Biotechnol. 2007 Nov;77(2):329-37. doi: 10.1007/s00253-007-1173-8. Epub 2007 Sep 9.
Esters are an important group of volatile compounds that can contribute to wine flavour. Wine lactic acid bacteria (LAB) have been shown to produce esterases capable of hydrolysing ester substrates. This study aims to characterise the esterase activities of nine LAB strains under important wine conditions, namely, acidic conditions, low temperature (to 10 degrees C) and in the presence of ethanol (2-18% v/v). Esterase substrate specificity was also examined using seven different ester substrates. The bacteria were generally found to have a broad pH activity range, with the majority of strains showing maximum activity close to pH 6.0. Exceptions included an Oenococcus oeni strain that retained most activity even down to a pH of 4.0. Most strains exhibited highest activity across the range 30-40 degrees C. Increasing ethanol concentration stimulated activity in some of the strains. In particular, O. oeni showed an increase in activity up to a maximum ethanol concentration of around 16%. Generally, strains were found to have greater activity towards short-chained esters (C2-C8) compared to long-chained esters (C10-C18). Even though the optimal physicochemical conditions for enzyme activity differed from those found in wine, these findings are of potential importance to oenology because significant activities remained under wine-like conditions.
酯类是一类重要的挥发性化合物，可影响葡萄酒的风味。已证明葡萄酒乳酸菌（LAB）能产生可水解酯底物的酯酶。本研究旨在表征9株LAB菌株在重要葡萄酒条件下的酯酶活性，这些条件包括酸性条件、低温（至10摄氏度）以及存在乙醇（2-18% v/v）的情况。还使用7种不同的酯底物检测了酯酶的底物特异性。一般发现这些细菌具有较宽的pH活性范围，大多数菌株在接近pH 6.0时显示出最大活性。例外情况包括一株酒类酒球菌菌株，即使在pH低至4.0时仍保留大部分活性。大多数菌株在30-40摄氏度范围内表现出最高活性。乙醇浓度的增加刺激了一些菌株的活性。特别是，酒类酒球菌在乙醇浓度高达约16%时活性增加。一般来说，与长链酯（C10-C18）相比，菌株对短链酯（C2-C8）的活性更高。尽管酶活性的最佳理化条件与葡萄酒中的条件不同，但这些发现对酿酒学具有潜在重要性，因为在类似葡萄酒的条件下仍存在显著活性。
