Biotechnology Letters, Vol.39, No.3, 391-396, 2017
Enhanced production of fructosyltransferase in Aspergillus oryzae by genome shuffling
To breed Aspergillus oryzae strains with high fructosyltransferase (FTase) activity using intraspecific protoplast fusion via genome-shuffling. A candidate library was developed using UV/LiCl of the conidia of A. oryzae SBB201. By screening for enzyme activity and cell biomass, two mutants (UV-11 and UV-76) were chosen for protoplast fusion and subsequent genome shuffling. After three rounds of genome recombination, a fusion mutant RIII-7 was obtained. Its FTase activity was 180 U g(-1), approximately double that of the original strain, and RIII-7 was genetically stable. In fermentation culture, FTase activity of the genome-shuffled strain reached a maximum of 353 U g(-1) using substrate-feeding method, and this value was approximately 3.4-times higher than that of the original strain A. oryzae SBB201. Intraspecific protoplast fusion of A. oryzae significantly enhanced FTase activity and generated a potentially useful strain for industrial production.
Keywords:Aspergillus oryzae;Fructooligosaccharides;Fructosyltransferase;Genome shuffling;Protoplast fusion