Description:
<jats:title>Summary</jats:title><jats:p>To set a benchmark in fungal growth rate, a differential analysis of prototrophic <jats:italic>Aspergillus fumigatus</jats:italic> AR04 with three ascomycetes applied in > 10<jats:sup>3</jats:sup> t year<jats:sup>‐1</jats:sup> scale was performed, i.e. <jats:italic>Ashbya gosspyii</jats:italic> (riboflavin), <jats:italic>Aspergillus niger</jats:italic> (citric acid) and <jats:italic>Aspergillus oryzae</jats:italic> (food‐processing). While radial colony growth decreased 0.5‐fold when <jats:italic>A</jats:italic>. <jats:italic>gossypii</jats:italic> was cultivated at 40°C instead of 28°C, <jats:italic>A. fumigatus</jats:italic> AR04 responded with 1.7‐fold faster hyphal growth. <jats:italic>A</jats:italic>. <jats:italic>niger</jats:italic> and <jats:italic>A. oryzae</jats:italic> formed colonies at 40°C, but not at 43°C. Moreover, all <jats:italic>A. fumigatus</jats:italic> strains tested grew even at 49°C. In chemostat experiments, <jats:italic>A</jats:italic>. <jats:italic>fumigatus</jats:italic> AR04 reached steady state at a dilution rate of 0.7 h<jats:sup>‐1</jats:sup> at 40°C, 120% more than reported for <jats:italic>A. gossypii</jats:italic> at 28°C. To study mycelial growth rates under unlimited conditions, carbon dioxide increase rates were calculated from concentrations detected online in the exhaust of batch fermentations for 3 h only. All rates calculated suggest that <jats:italic>A. fumigatus</jats:italic> AR04 approximates Arrhenius’ rule when comparing short cultivations at 30°C with those at 40°C. Linearization of the exponential phase and comparison of the slopes revealed an increase to 192% by the 10°C up‐shift.</jats:p>