Fig. 5

Volumetric activity of cellobiohydrolase and \(\upbeta\)-glucosidase for different combinations of glucose and lactose. The experiment with 0 g l\(^{-1}\) lactose and 20 g l\(^{-1}\) glucose resulted in the lowest cellobiohydrolase and \(\upbeta\)-glucosidase activities, measuring at 120 ± 6 U l\(^{-1}\) and 106 ± 4 U l\(^{-1}\). The highest cellulase activities of 400 ± 14 U l\(^{-1}\) and 311 ± 43 U l\(^{-1}\) were achieved when lactose was used as the sole carbon source. This represents a threefold increase in activity compared to the standard batch approach using glucose as the sole carbon source. Cultivation conditions: RutC30, RWP, adapted medium, n = 1000 rpm, \({\text{d}_{0}}=3\) mm, \({\text{V}_\text{W}}=3.4\) ml, \({\text{V}_\text{L}}=1\) ml, humidity \(\ge 85\)%, \({\text{O}_{2}}=35\)%, T = 30 \(^\circ\)C, inoculum = 10\(^{5}\) spores ml\(^{-1}\)