American Journal of Biochemistry and Biotechnology

Optimum Conditions for Measuring Dehydrogenase Activity of Aspergillus niger using TTC

A. E. Ghaly and N. S. Mahmoud

DOI : 10.3844/ajbbsp.2006.186.194

American Journal of Biochemistry and Biotechnology

Volume 2, Issue 4

Pages 186-194


The suitability of the triphenyl tetrazolium chloride (TTC) for dehydrogenase activity measurement of the vegetative cells of the fungal species Aspergillus niger was investigated. The triphenyl formazan (TF) yield increased with the increases in TTC concentration, pH, temperature and incubation time within the studied ranges. The effects of individual parameters, as well as the combined effects, on the TF yield were found to follow exponential expressions. The sensitivity analysis showed that the TF yield is more sensitive to changes in temperature followed by pH, TTC concentration and incubation time. Although the rate of increase in the enzyme activity decreased gradually with the increase in temperature, no enzyme denaturation was observer below 55 ºC. The optimum TTC-test conditions for measuring the dehydrogenase activity of A. niger vegetative cells are a TTC concentration of 15 g/L, a pH of 9, a temperature of 55 ºC and an incubation time of 4 h. Although the procedure has been successfully tested with mycelia of different stages of growth, it would be interesting to test the effects of different stages of growth on TTC reduction under both aerobic and anaerobic conditions.


© 2006 A. E. Ghaly and N. S. Mahmoud. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.