Open AccessGrowth of the salt‐tolerant yeast Zygosaccharomyces rouxii in microtiter plates: effects of NaCl, pH and temperature on growth and fusel alcohol production from branched‐chain amino acids
Author(s) -
Jansen Michael,
Veurink Janine H,
Euverink GertJan W,
Dijkhuizen Lubbert
Publication year - 2003
Publication title -
fems yeast research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.991
H-Index - 92
eISSN - 1567-1364
pISSN - 1567-1356
DOI - 10.1111/j.1567-1364.2003.tb00172.x
Subject(s) - fusel alcohol , biology , yeast , biochemistry , salt (chemistry) , amino acid , isobutanol , yeast extract , food science , saccharomyces cerevisiae , alcohol , fermentation , chemistry , organic chemistry
Zygosaccharomyces rouxii , a salt‐tolerant yeast isolated from the soy sauce process, produces fusel alcohols (isoamyl alcohol, active amyl alcohol and isobutyl alcohol) from branched‐chain amino acids (leucine, isoleucine and valine, respectively) via the Ehrlich pathway. Using a high‐throughput screening approach in microtiter plates, we have studied the effects of pH, temperature and salt concentration on growth of Z. rouxii and formation of fusel alcohols from branched‐chain amino acids. Application of minor variations in pH (range 3–7) and NaCl concentrations (range 0–20%) per microtiter plate well allowed a rapid and detailed evaluation of fermentation conditions for optimal growth and metabolite production. Conditions yielding the highest cell densities were not optimal for fusel alcohol production. Maximal fusel alcohol production occurred at low pH (3.0–4.0) and low NaCl concentrations (0–4%) at 25°C. At pH 4.0–6.0 and 0–18% NaCl, considerable amounts of α‐keto acids, the deaminated products from the branched‐chain amino acids, accumulated extracellularly. The highest cell densities were obtained in plates incubated at 30°C. The results obtained under various incubation conditions with (deep‐well) microtiter plates were validated in Erlenmeyer shake‐flask cultures.