Hexose Fermentation By The Fission Yeast Schizosaccharomyces pombe and Characterization of its Hexokinase
thesis
posted on 2020-01-17, 03:04 authored by ESTER MPANDI-KHOSAThis thesis describes a study of some aspects of ethanol production by the fission yeast Schizosaccharomyces pombe and the purification and characterization of its hexokinase.
Comparisons were made between S. pombe MY4 (also L972) and new isolates of S. pombe (from molasses) and Saccharomyces cerevisiae (from a preparation used for industrial production of ethanol) obtained in Zimbabwe. All three strains of yeasts produced ethanol with high efficiency and although the strain of Saccharomyces cerevisiae was somewhat more tolerant of ethanol than the two strains of S. pombe, the latter were more tolerant of high concentrations of sugars, growing in up to 60% (w/v) sucrose.
Studies on S. pombe MY 4 showed that its optimum pH for growth and ethanol production was less than 5.5, and it had a requirement for air during fermentation of glucose. When growing on sucrose the extent of growth was reduced by concentrations above 20% (w/v), probably due to inhibition by the accumulating ethanol, since ethanol increased the growth inhibiting effect of high concentrations of sucrose. This inhibition could be overcome by carrying out the fermentation under reduced pressure and removing the ethanol as it was formed.[...]
Comparisons were made between S. pombe MY4 (also L972) and new isolates of S. pombe (from molasses) and Saccharomyces cerevisiae (from a preparation used for industrial production of ethanol) obtained in Zimbabwe. All three strains of yeasts produced ethanol with high efficiency and although the strain of Saccharomyces cerevisiae was somewhat more tolerant of ethanol than the two strains of S. pombe, the latter were more tolerant of high concentrations of sugars, growing in up to 60% (w/v) sucrose.
Studies on S. pombe MY 4 showed that its optimum pH for growth and ethanol production was less than 5.5, and it had a requirement for air during fermentation of glucose. When growing on sucrose the extent of growth was reduced by concentrations above 20% (w/v), probably due to inhibition by the accumulating ethanol, since ethanol increased the growth inhibiting effect of high concentrations of sucrose. This inhibition could be overcome by carrying out the fermentation under reduced pressure and removing the ethanol as it was formed.[...]
