Formation of autodiploid strains in Aspergillus niger and their application to citric acid production from starch

Industrial Production of Antibiotics in Fungi: Current State, Deciphering the Molecular Basis of Classical Strain Improvement and Increasing the Production of High-Yielding Strains by the Addition of Low-Molecular Weight Inducers

“…In order to force a fungal strain to synthesize much more of a natural product than is intended by its physiology (100-1000 or more times), there are a number of biotechnological tools, such as: (i) random mutagenesis with physical and/or chemical mutagens and screening [78,109,132]; (ii) sexual crossing [133][134][135][136]; (iii) somatic crossing (including parasexual recombination) [137][138][139]; and (iv) genetic engineering [76,140,141]. The first three methods belong to the so-called classical strain improvement (CSI) methods.…”

Effect of water activity on invertase production in solid state fermentation by improved diploid strains of Aspergillus niger

“…Routine experiments consisted of 27 ml of a spore suspension, at a concentration of 8 × 10 6 spores/ml, irradiated with UV light at 350 W/cm 2 . The low numbers of mutants induced in these conditions was compensated by a filtration enrichment method as described previously [5][6][7][8][9][10][11][12][13][14][15][16][17]. One phenylalanine auxotroph (Aw96PHEN) was isolated from strain Aw96-4.…”

“…In order to increase the production of different metabolites by Aspergillus strains, parasexual crosses between selected strains may be considered. This strategy has been used to enhance the production levels of metabolites, enzymes [5], recombinant proteins [13] and citric acid [14].…”

Improvement of xylanase production by a parasexual cross between Aspergillus niger strains

“…It was also observed as a naturally occurring phenomenon in other species within the genera Aspergillus (Pontecorvo, 1956). In order to increase the production of different metabolites by Aspergillus strains, parasexual crosses between selected strains have been used to enhance the production levels of metabolites such recombinant proteins (Bodie et al, 1994) and citric acid (Sarangbin et al, 1994). Antier et al (1993) used the toxic glucose analogue 2-deoxy-D-glucose (2DG) to isolate improved Aspergillus niger strains resistant to this compound.…”