Protease-deficient mutants of the Quorn® mycoprotein fungus, Fusarium graminearum A3/5

• Published in: FEMS microbiology letters 1998-01, Vol.158 (2), p.231-236
• Main Authors: Griffen, Alison M, Novakova, Michaela, Mokhtar, Seri I, Wiebe, Marilyn G, Robson, Geoffrey D, Trinci, Anthony P.J
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; Colonial mutant; Continuous flow culture; Fundamental and applied biological sciences. Psychology; Fusarium graminearum; Microbiology; Morphological mutant; Mycology; Pathogenicity, host-agent relations, miscellaneous strains, epidemiology; plant biochemistry; plant breeding; plant genetics; plant physiology; Protease-deficient mutant; Transformant
• ISSN: 0378-1097; 1574-6968
• DOI: 10.1016/S0378-1097(97)00527-2

Protease-deficient mutants of two highly branched (colonial) mutants of the Quorn® mycoprotein fungus, Fusarium graminearum A3/5, were generated by UV mutagenesis. One protease-deficient mutant of each strain was studied in glucose-limited chemostat culture ( D=0.17 h −1, pH=5.8) with 5 g casein l −1 added to the medium and they were found to produce no or very little aspartic protease, which is produced by the parental strains under the same conditions. In chemostat culture the protease-deficient mutants were unstable with respect to lack of proteolytic activity regardless of whether or not casein (500 mg l −1) was included in the medium. At low dilution rate ( D=0.07 h −1) or at increased pH (pH=6.9), the parental strains produced other proteases in addition to the aspartic protease.