P78: The Ashbya gossypii purine salvage pathways as a potential source of nucleotides IMP and GMP

The fungus Ashbya gossypii belongs to the hemiascomycete group, which includes many species used in a wide variety of biotech processes. In contrast to the yeast hemiascomycetes such as S. cerevisiae and P. pastoris, A. gossypii shows filamentous growth with multinucleated and extensively branching hyphae, many of which undergo cellular lysis when the culture becomes older. Concomitant with hyphae lysis an extensive intracellular breakdown also takes place at the end of stationary phase of the culture. As part of the degradation byproducts released to the medium, nucleobases, nucleosides and nucleotides derived from the hydrolysis of nucleic acids can be detected in noticeable amounts. Since purine nucleotides IMP and GMP have important applications in the cosmetic and food industries we are exploring the possibility of using fermentation of A. gossypii as a source of these compounds. In contrast to the highly conserved de novo pathway, the network of the purine salvage pathways varies considerably among the different organisms. A hypothetical salvage pathway for A. gossypii was deduced by genome-wide comparison of related organisms. The A. gossypii purine salvage pathways were confirmed by genetic and biochemical approaches and contribution of this enzymatic network to the formation of IMP and GMP is being evaluated.