ISOLATION AND CHARACTERIZATION OF MUTANTS OF ASPERGILLUS NIGER DEFICIENT IN EXTRACELLULAR PROTEASES
黑曲霉蛋白酶缺陷突变体的分离和鉴定

Several mutants of Aspergillus niger 3 795 , deficient in extracellular protease expression, have been isolated and characterized biochemically after in vivro UV mutagenesis of conidiospores and selected by halo screening on the gelatin/casein plate and skim milk plate. Extracellular proteolytic activities of 3 795 1 23 and 3 795 1 30 are 5.4% and 8.4% of the parental strain and these strains may be used as the host for efficient expression of foreign proteins.