Optimization and Scale-up Studies for the Production of Biosurfactant by Saccharomyces cerevisiae 2031 in a Stirred Tank Bioreactor using Molasses and Coco Paring Meal as Substrate
Author : Salvador, Jhun Mark Suanson
Major Adviser : Alfafara, Catalino G.
Major Co-Adviser : Elegado, Franciso B.
Committee Members : Capunitan, Jewel A.; Detras, Monet Concepcion M.; Alcantara, Jerico Z.
Year : 2015
Month : June
Type : Thesis
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The production of biosurfactant from Saccharomyces cerevisiae 2031 was optimized in a 5-L stirred tank bioreactor via Response Surface Methodology (RSM), and the results were used to scale up the process to a 30-L stirred tank bioreactor. RSM experiments showed that maximum yeast biomass (proportional to biosurfactant content) was achieved at combinations of either (a) high aeration and high agitation or (b) high aeration and low agitation. On the other hand, the effect of aeration and agitation on the emulsification index was not clearly determined indicating possible inadequate extraction of biosurfactant from yeast cell wall. Thus, considering the proportional relationship of biomass and biosurfactant concentrations, numerical optimization was applied to maximize biomass concentration in the 5-L bioreactor. Optimum biosurfactant production was found at 1.34 vvm aeration and 159 rpm agitation. Experimental verification showed validity of the optimum conditions (5-L bioreactor). Using the volumetric oxygen mass transfer coefficient (kₗa) as a scale up factor, the equivalent aeration/agitation conditions were calculated for a 30-L bioreactor as 1.34 vvm, 88 rpm. Verification of the equivalent optimum conditions in the scaled-up 30-L bioreactor showed reproducibility of optimum fermentation performance of the 5-L bioreactor, indicating successful optimization and scale-up.
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