Invertase activity of intact cells of Saccharomyces cerevisiae growing on sugarcane molasses. II. Unsteady-state continuous-culture tests.
During unsteady-state continuous culture of Saccharomyces cerevisiae on sugarcane blackstrap molasses, the invertase activity of the intact yeast cells oscillated. Disturbances were produced by changing medium composition, air rate, impeller speed, and dilution rate. The influence of the oxygen supply rate and of the dilution rate on the invertase activity depend on the medium composition. The highest invertase activity was obtained when, after a steady-state attained using unsupplemented culture medium, nutrients were added to the feeding mash. A Monod-like equation seems to be the best representation of the correlation between the specific rate of reducing sugars consumption and the specific rate of nonreducing sugar hydrolysis by the yeast cells.
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Biochemical and Pharmaceutical Technology Department, Faculdade de Ciências Farmacêuticas, University of São Paulo, C.P. 30786, 01000, São Paulo, SP, Brazil.
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Borzani
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