ABSTRACT
Ageing as always been part of the biological life and a topic that we understand very little of. In particular, ageing in microbial cultures undergoing long-term industrial fermentation is a very important factor determining the overall efficiency and in final analysis the economic outcome of the bio-production process. On the other hand, gross chromosomal rearrangements (GCR), specifically translocations, are genomic alteration well known to occur in fungal cells undergoing long-term growth. This work focuses primarily on the effects of chromosome translocation on the chronological life span (CLS) of Saccharomyces cerevisiae (SC), a model organism used both, for understanding the ageing process as well as for industrial large-scale production of re-cyclable
biomass. A secondary goal of the research was to verify the feasibility of using telomeric DNA sequence length as a molecular marker to monitor population ageing during long-term fermentation. Therefore, a comparison between telomere length and CLS was performed. The data that have been gathered show that chromosome translocation has a different and sometimes opposite effect on the CLS of the budding yeast; furthermore, it was demonstrated that in some cases telomere length does not correlate with the life span of SC. This finding refutes the postulate that age and life expectancy can be deduced from the length of the telomeric DNA and thus precludes the possibility to use this parameter to monitor the health and viability of a long-term industrial fermentation process. 1.1 Introduction
Saccharomyces cerevisiae, also known as the budding yeast, has been used since the dawn of the great civilizations for its fermentation properties in the production of bread, beer, and wine (Fig. 1.1).
