Kinetics and modeling of temperature effects on batch xanthan gum fermentation

Abstract

Batch fermentation kinetics of xanthan gum production from glucose by Xanthomonas campestris at temperatures between 22 degrees C and 35 degrees C were studied to evaluate temperature effects on cell growth and xanthan formation. These batch xanthan fermentations were modeled by the logistic equation for cell growth, the Luedeking-Piret equation for xanthan production, and a modified Luedeking-Piret equation for glucose consumption. Temperature dependence of the parameters in this model was evaluated. Growth-associated rate constants increased to a maximum at approximately 30 degrees C and then decreased to zero at approximately 35 degrees C. This temperature effect can be modeled using a square-root model. On the contrary, non-growth-associated rate constants increased with increasing temperature, following the Arrhenius relationship, in the entire temperature range studied. The model developed in this work fits the experimental data very well and can be used in a simulation study. However, due to the empirical nature of the model, the parameter values need to be reevaluated if the model is to be applied to different growth conditions.

Optimisation of xanthan gum production by palm date (Phoenix dactylifera L.) juice by-products using response surface methodology

“…In fact, similar results were achieved in previous studies (Shu & Yang, 1990, 1991, reporting that at temperature values lower than 35-25°C, cells grow better, and that higher mass production do not lead to high xanthan gum production.…”

Kinetic models for xanthan gum production using Xanthomonas campestris from molasses

“…The optimum temperature for maximum growth was obtained, since X. campestris showed the desired biological activities for xanthan production. Effect temperature on xanthan production has been investigated by others; the optimum reported temperature was in the range 30-33 °C [15,20,21]. Maximum xanthan gum production was obtained at 32 °C.…”

“…(3) into Eq. (2) followed by integration, resulted in the following equation for the cell concentration [15]:…”

“…Several models have been suggested to estimate the concentration of xanthan in fermentation broth [15]. Malthus, logistic, Luedeking-Piret and modified Luedeking--Piret kinetic models have been discussed for substrate utilization, cell growth rate and xanthan gum production [9].…”

Measurement processing for state estimation and fault identification in batch fermentations

“…Equations µ(u), X S (u), a(u) and b(u) and K R (u) represent the kinetic parameters as functions of the temperature [Shu and Yang, 1991]. ∆µ, ∆X S , ∆a, ∆b and ∆K R are disturbance parameters used to compensate for the uncertainty of these functions in respect to the complex fermentation dynamic.…”