Modelling the effect of temperature, water activity and solute on the in vitro growth of the biocontrol yeast Pichia anomala strain K

• Main Authors: Jijakli M.H., Serrhini M.N., Bajji M., Lahlali R.
• Format: Article
• Language: English
• Published: Presses Agronomiques de Gembloux 2008-01-01
• Series: Biotechnologie, Agronomie, Société et Environnement
• Subjects: glucose; glycerol; NaCl; Pichia anomala strain K; predictive models; response surface methodology; sorbitol
• Online Access: http://www.pressesagro.be/base/text/v12n4/353.pdf

The objective of this work was to evaluate and model the combined effect of temperature (5-25°C) and water activity (aw, 0.890-0.980) on Pichia anomala strain K growth and lag phase. Variance analysis showed a highly significant effect of aw, solute and temperature on strain K growth. The decrease of aw and temperature significantly reduced and delayed growth, the effect being more drastic with NaCl compared to the other solutes. Response surface models relating the natural logarithm of growth with aw and temperature were developed for each solute. Optimum growth was obtained at aw values ranging from 0.980 to 0.995 at 25°C. For all models, there was good agreement between observed and predicted values. However, only models based on sorbitol and glucose accurately described experimental growth data. Implementation of the present results in combination with our previous findings on four main post-harvest pathogens should result in a more effective biocontrol strategy to limit fruit losses