Browsing by Subject "kinetics"

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    The effect of growth factors on anoxic chemostat cultures of two Saccharomyces cerevisiae strains
    (Springer, 2001) De Kock, S H; Du Preez, J C; Kilian, S G
    In anoxic chemostat cultures of Saccharomyces cerevisiae ATCC 4126 and CBS 8066 grown in a medium containing yeast extract, a sharp increase in the steady-state residual glucose concentration occurred at relatively low dilution rates, contrary to the expected Monod kinetics. However, supplementation with vitamins and amino acids facilitated efficient glucose uptake. This enhanced requirement for growth factors under anoxic conditions and at high growth rates could explain the exceptionally high apparent ks values for S. cerevisiae reported in the literature.
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    On modifying the Arrhenius equation to compensate for temperature changes for reactions within biological systems
    (South African Water Research Commission, 2012) Sheridan, Craig; Petersen, Jochen; Rohwer, Johann
    In this communiqué, we discuss the use of the Arrhenius relationship to describe the temperature dependence of reacting biological systems, such as those treating wastewater. We also discuss the use of the modified Arrhenius function, and those instances where its applicability is limited. We show that the error when using the modified relationship is 7% at 30°C, 15% at 40°C and 25% at 50°C. We conclude that whilst the modified relationship is acceptable at lower temperatures, in those applications where higher temperatures are reached (above 25°C) the error with using the relationship may not be acceptable. We present an Arrhenius equation for use in biological systems, which is applicable for all temperature ranges.