Evolutionary Adaptation as a Tool to Generate Targeted Mutant Strains as Evidence by Increased Inulinase Production in Aspergillus oryzae
Helena Culleton, Eline Majoor, Vincent A. McKie and Ronald P. de Vries
from: Aspergillus and Penicillium in the Post-genomic Era (Edited by: Ronald P. de Vries, Isabelle Benoit Gelber and Mikael Rørdam Andersen). Caister Academic Press, U.K. (2016) Pages: 189-196.
Inulin is found widely distributed in nature as a storage polysaccharide and consists of a linear polymer of β-1,2-linked D-fructose molecules which can be hydrolyzed by endo-/exo-inulinases and fructofuranosidase (invertase) to give D-fructose and fructooligosaccharides. In this study we aimed to improve the inulin degradation potential of Aspergillus oryzae through the upregulation of exo-inulinase production using an evolutionary adaptation method. This method has the advantage over UV or chemical mutagenesis in that it is likely to have a lower number of random mutations as only beneficial mutations will provide a competitive advantage and will therefore become dominant in the culture. As an organism with no predicted endo-inulinase function, improved inulin degradation in A. oryzae would be largely dependent on the overproduction of this enzyme. Subsequent generation growth of Aspergillus oryzae (Rib40) on inulin for 9 weeks successfully resulted in exo-inulinase overproducing mutants read more ...