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Title: Design and analysis of immobilized cell reactors

Thesis/Dissertation ·
OSTI ID:5283117

In this study, two novel bioreactors were developed to carry out fermentation by immobilized cells. Conventional chemical process equipment such as spouted-bed fluid-agitated reactor and shell-tube cross-current evaporator designs were adapted for anaerobic fermentation of glucose to ethanol by immobilized Saccharomyces cerevisiae. The yeast cells were immobilized by a modified gel entrapment method and micron-sized silica was incorporated to impart several desirable properties to the gel particles. The new reactor configurations demonstrated an efficient deployment of the microorganisms over long periods of continuous operation. Periodic aeration of the fluid-agitated bioreactor yielded high productivity by regenerating the biocatalyst due to the facultative nature of the organism used in this study. Internal diffusion processes were modeled for spherical particles containing immobilized cells. A general kinetic model developed for free cell fermentation was used to correlate effectiveness factor with the process conditions. Under product inhibition conditions, this design helped to achieve high product concentration (10% w/v ethanol) at an optimum temperature of 30/sup 0/C. The cell concentration in the immobilized phase was directly related to the local growth rate and the free cells in the product stream were found to characterize the rate of reproduction of the immobilized cells. The immobilized cell growth effects were analyzed by modeling the temperature dependences of the product inhibition and the doubling rate.

Research Organization:
Rutgers-the State Univ., New Brunswick, NJ (USA)
OSTI ID:
5283117
Resource Relation:
Other Information: Thesis (Ph. D.)
Country of Publication:
United States
Language:
English