Analysis of Growth Inhibition and Metabolism of Hydroxycinnamic Acids by Brewing and Spoilage Strains of Brettanomyces Yeast.

Michael Lentz,Chad Harris

doi:10.3390/foods4040581

Abstract

Brettanomyces yeasts are well-known as spoilage organisms in both the wine and beer industries, but also contribute important desirable characters to certain beer styles. These properties are mediated in large part by Brettanomyces’ metabolism of hydroxycinnamic acids (HCAs) present in beverage raw materials. Here we compare growth inhibition by, and metabolism of, HCAs among commercial brewing strains and spoilage strains of B. bruxellensis and B. anomalus. These properties vary widely among the different strains tested and between the HCAs analyzed. Brewing strains showed more efficient metabolism of ferulic acid over p-coumaric acid, a trait not shared among the spoilage strains.

Highlights

Brettanomyces yeast are ubiquitous around the world and are commonly encountered in commercial fermentation settings
Teleomorph forms have been reported for B. bruxellensis and B. anomalus and are identified as the Dekkera genus [1]; these forms are rare and Brettanomyces will be used in this manuscript
The Minimum inhibitory concentration (MIC) for each strain was tested in ferulic acid, p-coumaric acid, and caffeic acid from 0–20 mM

Summary

Introduction

Brettanomyces yeast are ubiquitous around the world and are commonly encountered in commercial fermentation settings. Brettanomyces are slow growing, and do not compete well with Saccharomyces yeast during active fermentation Since they are tolerant of low pH and high alcohol, and can metabolize sugars and other organic molecules left behind by Saccharomyces, they may gain a foothold in a wine near the end of fermentation or during aging [2,7]. If they are allowed to persist, the wine may develop “Brett taint”, a characteristic set of off-flavors and aromas often described as rubber, burnt plastic, medicinal, leathery, goaty, barnyard, etc. Brettanomyces’ full metabolic contribution to wine flavor and aroma is poorly understood, the characteristics described above are primarily attributed to these yeasts’ ability to metabolize hydroxycinnamic acids (HCAs) [8,9]

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