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BioMed Research International
Volume 2013, Article ID 409675, 9 pages
Research Article

Enhancement of Oxygen Mass Transfer and Gas Holdup Using Palm Oil in Stirred Tank Bioreactors with Xanthan Solutions as Simulated Viscous Fermentation Broths

1Faculty of Chemical Engineering, Universiti Teknologi MARA (UiTM), 40450 Shah Alam, Selangor, Malaysia
2Faculty of Chemical Engineering, Manipal International University, 71800 Nilai, Negeri Sembilan Darul Khusus, Malaysia

Received 13 August 2013; Accepted 1 October 2013

Academic Editor: Eldon R. Rene

Copyright © 2013 Suhaila Mohd Sauid et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Volumetric mass transfer coefficient ( ) is an important parameter in bioreactors handling viscous fermentations such as xanthan gum production, as it affects the reactor performance and productivity. Published literatures showed that adding an organic phase such as hydrocarbons or vegetable oil could increase the . The present study opted for palm oil as the organic phase as it is plentiful in Malaysia. Experiments were carried out to study the effect of viscosity, gas holdup, and on the xanthan solution with different palm oil fractions by varying the agitation rate and aeration rate in a 5 L bench-top bioreactor fitted with twin Rushton turbines. Results showed that 10% (v/v) of palm oil raised the of xanthan solution by 1.5 to 3 folds with the highest value of 84.44 h−1. It was also found that palm oil increased the gas holdup and viscosity of the xanthan solution. The values obtained as a function of power input, superficial gas velocity, and palm oil fraction were validated by two different empirical equations. Similarly, the gas holdup obtained as a function of power input and superficial gas velocity was validated by another empirical equation. All correlations were found to fit well with higher determination coefficients.