Ethanol-induced water stress and fungal growth

John E. Hallsworth*, Yoshiyuki Nomura, Masayoshi Iwahara

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

49 Citations (Scopus)

Abstract

Fungal growth inhibition by ethanol was compared with that caused by five other agents of water stress (at 25, 40 and 42.5°C), using Aspergillus oryzae. Ethanol, KCl, glycerol, glucose, sorbitol, and polyethylene glycol 400 were incorporated into media at concentrations corresponding to water activity (a(w)) values in the range 1 to 0.75. Generally, as temperature increased there was a decrease in the a(w) value at which optimum growth occurred. The a(w) limit for growth on KCl, glycerol, glucose, sorbitol, or polyethylene glycol 400 media was about 0.85, regardless of temperature. However, the a(w) limit for growth on ethanol media varied between 0.97 and 0.99 a(w) and was temperature-dependent. Water stress accounted for up to 31, 18 and 6% of growth inhibition by ethanol at 25, 40, and 42.5°C, respectively. For media containing ethanol, the decrease in growth rate per unit of a(w) reduction was greater as temperature increased. However, ethanol-induced water stress remained constant regardless of temperature, suggesting that other inhibitory effects of ethanol are closely temperature- dependent. Water stress may account for considerably more than 30% of growth inhibition by ethanol in cells that remain metabolically active at higher ethanol concentrations.
Original languageEnglish
Pages (from-to)451-456
Number of pages6
JournalJournal of Fermentation and Bioengineering
Volume86
Issue number5
DOIs
Publication statusPublished - 01 Dec 1998

Keywords

  • Aspergillus oryzae
  • Ethanol toxicity
  • Growth inhibition
  • Mode-of- action
  • Osmotic stress
  • Water activity

ASJC Scopus subject areas

  • Biotechnology
  • Applied Microbiology and Biotechnology

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