Synthesis of fruity ethyl esters by acyl coenzyme A: alcohol acyltransferase and reverse esterase activities in Oenococcus oeni and Lactobacillus plantarum
Article first published online: 11 JAN 2013
© 2012 Australian Wine Research Institute © 2012 The Society for Applied Microbiology
Journal of Applied Microbiology
Volume 114, Issue 3, pages 797–806, March 2013
How to Cite
Costello, P.J., Siebert, T.E., Solomon, M.R. and Bartowsky, E.J. (2013), Synthesis of fruity ethyl esters by acyl coenzyme A: alcohol acyltransferase and reverse esterase activities in Oenococcus oeni and Lactobacillus plantarum. Journal of Applied Microbiology, 114: 797–806. doi: 10.1111/jam.12098
- Issue published online: 18 FEB 2013
- Article first published online: 11 JAN 2013
- Accepted manuscript online: 6 DEC 2012 07:04AM EST
- Manuscript Accepted: 3 DEC 2012
- Manuscript Revised: 22 NOV 2012
- Manuscript Received: 9 OCT 2012
- Grape and Wine Research and Development Corporation
- alcohol acyltransferase;
- ester biosynthesis;
- Lactobacillus plantarum ;
- malolactic fermentation;
- Oenococcus oeni
To assess the abilities of commercial wine lactic acid bacteria (LAB) to synthesize potentially flavour active fatty acid ethyl esters and determine mechanisms involved in their production.
Methods and Results
Oenococcus oeni AWRI B551 produced significant levels of ethyl hexanoate and ethyl octanoate following growth in an ethanolic test medium, and ester formation generally increased with increasing pH (4·5 > 3·5), anaerobiosis and precursor supplementation. Cell-free extracts of commercial O. oeni strains and Lactobacillus plantarum AWRI B740 were also tested for ester-synthesizing capabilities in a phosphate buffer via: (i) acyl coenzyme A: alcohol acyltransferase (AcoAAAT) activity and (ii) reverse esterase activity. For both ester-synthesizing activities, strain-dependent variation was observed, with AcoAAAT activity generally greater than reverse esterase. Reverse esterase in O. oeni AWRI B551 also esterified 1-propanol to produce propyl octanoate, and deuterated substrates ([2H6]ethanol and [2H15]octanoic acid) to produce the fully deuterated ester, [2H5]ethyl [2H15]octanoate.
Wine LAB exhibit ethyl ester-synthesizing capability and possess two different ester-synthesizing activities, one of which is associated with an acyl coenzyme A: alcohol acyltransferase.
Significance and Impact of the Study
This study demonstrates that wine LAB exhibit enzyme activities that can augment the ethyl ester content of wine. This knowledge will facilitate greater control over the impacts of malolactic fermentation on the fruity sensory properties and quality of wine.