Effect of sugar consumption on ethanol fermentation in a tower fermentor packed with self-aggregating yeast
A strain of self-aggregatingSaccharomyces uvarum was cultivated in a 6-L tower fermentor for continuous ethanol fermentation. Large aggregates (2–3 mm) were formed and packed in the column. The height of this packed region depends on the sugar concentration. As sugar concentrations were reduced to below a critical value, most of the large aggregates disintegrated into smaller aggregates (0.1–0.2 mm). Above the packed bed region, small aggregates and small amount of large aggregates were fluidized and formed a well mixed region by the liquid medium and the produced carbon dioxide. A mathematical model of a plug flow with consideration of axial dispersion and a Continuous Stirred Tank Reactor (CSTR) in series is proposed to describe such fermentor. The concentration profile of sugar can be simulated by this model. The height of the packed bed region can then be estimated based on the predetermined critical sugar concentration. Final ethanol concentration and the productivity of such fermentor can also be predicted.
Index EntriesYeast aggregates ethanol fermentation tower fermentor model
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