Peptone changes the timing and accumulation of morphological mutants of the Quorn® myco-protein fungus Fusarium graminearum A3/5 in glucose-limited chemostat cultures

Abstract

Fusarium graminearum A3/5 was grown at pH 5.8 and a dilution rate of 0.19 h−1 in glucose‐limited chemostat culture supplemented with mycological peptone for 528 h. Although the population changed (i.e. displayed periodic selection) at the same rate in supplemented (132±23 h) and unsupplemented cultures (124±12 h), highly branched mutants were detected much earlier in the former cultures than in the latter, although they failed to displace the sparsely branched parental population. It was demonstrated that the selective advantage (compared to A3/5) of some mutants isolated from unsupplemented glucose‐limited culture could be eliminated by addition of peptone to the medium, but that a general growth rate mutant retained its advantage in the peptone‐supplemented medium. These results could be used to improve the cost‐efficiency of the fermentation.

Screening Filamentous Tropical Fungi for their Nutritional Potential as Sources of Crude Proteins, Lipids and Minerals

“…Since there is an increasing interest of consumers in incorporating healthy habits, search for foods that benefit human health is a modern demand (Perring et al, 2005) and novel foodstuffs such as low fat fungal proteins may become the technologically developed food supplements of the next generation. Nevertheless, research in this area has been focused only on a few fungal species that were screened for their nutritional potential so far (Wiebe et al, 1998).…”

Evolution of a recombinant (gucoamylase‐producing) strain of Fusarium venenatum A3/5 in chemostat culture

“…Once a colonial mutant has appeared in a glucose-limited chemostat culture of F. venenatum A3/5 grown on (NH 4 ) 2 SO 4 at pH 5.8, it inevitably displaces the parental strain, even in cultures which have been subjected to fluctuations (except in cultures supplemented with mycological peptone; Wiebe et al, 1998). Although, as expected, T21-C1 displaced the sparse population in the (NH 4 ) 2 SO 4 chemostat (Table II), none of the highly branched mutants observed in the NaNO 3 chemostat displaced the sparse population.…”

“…The 13 highly branched mutants isolated from the NaNO 3 chemostat and the mutant (T21-C1) from the (NH 4 ) 2 SO 4 chemostat were assessed for their ability to complement each other and four colonial mutants of F. venenatum A3/5 isolated previously from glucose-limited chemostats grown on (NH 4 ) 2 SO 4 (mutants CC1-5, CC2-2, MC3-2, and CC1-7; Wiebe et al, 1992a), and one mutant isolated previously from a (NH 4 ) 2 SO 4 , glucose-limited chemostat supplemented with peptone (mutant A37-1; Wiebe et al, 1998). These mutants were chosen to be representative of other mutants which have been isolated from glucose-limited chemostat cultures (Fig.…”