The Influence of PH and Dissolved Oxygen Tension (DOT) on Mycelium Growth and Cellulase Production by Trichoderma Reesei

The influence of pH and dissolved oxygen tension (DOT) on mycelium growth and cellulase production by Trichoderma reesei was studied in this paper. The experiments were carried out with a cellulose of 10 g/l in a 10 L steam sterilizable bioreactor. The results have shown that H+ concentration was highly fluctuated in the growing and metabolizing periods of mycelium, which went against mycelium growth and cellulase production. Controlling pH to 4.8 was favorable to mycelium growth and cellulase production; the maximum mycelium mass concentration was increased from 2.60 g/l to 2.77 g/l; the maximum filter paper activity was raised from 1.87 IU/ml to 2.79 IU/ml. Meanwhile, the growth and metabolism of mycelium demand an appropriate dissolved oxygen tension (DOT). When the velocity of aeration was increased from 0.4 to 0.5vvm to improve the condition of dissolving oxygen, the mycelium mass concentration was increased from 2.77 g/l to 2.98g/l, and the filter paper activity was raised from 2.79 IU/ml to 2.98 IU/ml.