Nutrient control for stationary phase cellulase production in Trichoderma reesei Rut C-30

•Stationary phase Trichoderma reesei Rut C-30 for long-term cellulase production.•Phosphorus limited cellulase production for extended fermentation.•Airlift pellet fermentation of T. reesei Rut C-30 possible with nutrient limitation.

This work describes the use of nutrient limitations with Trichoderma reesei Rut C-30 to obtain a prolonged stationary phase cellulase production. This period of non-growth may allow for dependable cellulase production, extended fermentation periods, and the possibility to use pellet morphology for easy product separation. Phosphorus limitation was successful in halting growth and had a corresponding specific cellulase production of 5 ± 2 FPU/g-h. Combined with the addition of Triton X-100 for fungal pellet formation and low shear conditions, a stationary phase cellulase production period in excess of 300 h was achieved, with a constant enzyme production rate of 7 ± 1 FPU/g-h. While nitrogen limitation was also effective as a growth limiter, it, however, also prevented cellulase production.