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Simulation of Optimum Nutrition in Bioreactors

Radfar, Marjan | 2013

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 45260 (06)
  4. University: Sharif University of Technology
  5. Department: Chemical and Petroleum Engineering
  6. Advisor(s): Abdekhodaie, Mohammad Jafar; Mehrvar, Mehrab
  7. Abstract:
  8. In this study, a semi-structured model for the growth and production of lactase in an aerated bioreactor by Kluyveromyces marxianus, growing on cheese whey, was developed. Three modes of culture, consisting of batch, fed-batch and a controlled-release system were investigated. Modeling was based on three metabolic pathways, representing the growth of Kluyveromyces marxianus. Lactose and oxygen consumption, cell growth, and also lactase and ethanol production rates were determined in the model. Induction was considered as the governing mechanism for enzyme production. The model showed good agreement with the experimental data in batch and fed-batch cultures. Controlled-release system is a novel substrate feeding strategy which was introduced in this research. Such a system, operating in a batch mode, reduces the complexity of a fed-batch culture and improves the performance of the system. So that with the same lactase activity production rate in controlled-release system, biomass and ethanol final concentration incraesed 37.62% and 23.44%, respectively, in comparison to fed-batch culture. Consequently, bioreactors with controlled-release feeding strategy can be an alternative for fed-batch cultures, making possible the control of cell growth and lactase production more efficiently in order to prevent production of undesired products, like ethanol. The presented model constituted a sound basis for the optimization of culture mode, and to evaluate the effect of different parameters to predict the optimal condition
  9. Keywords:
  10. Lactase Enzyme ; Modeling ; CONTROLLED RELEASE ; Fed-Batch Culture ; Batch Culture ; Metabolic Pathway ; Kluyveromyces Marxianus

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